From 16c7eb41354c3c1ca5fca08bd0501568fa2b5212 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Fri, 3 Jan 2014 21:25:18 +0100
Subject: [PATCH 01/11] Speed up `realpath()` with dynamically loaded C
 extension

On systems that support both C compiling and dynamic loading, we can
speed up `realpath()` (where most time in rbenv is spent) by replacing
it with a dynamically loaded bash builtin.

When `make -C src` is called in the project's root,
`libexec/rbenv-realpath.dylib` will be created. If it exists, rbenv will
attempt to load it as a builtin command. If it fails, execution will
fall back to the old `realpath()` shell function.
---
 .gitignore          |  2 ++
 libexec/rbenv-hooks |  4 +++-
 src/Makefile        | 10 ++++++++++
 src/bash.h          | 31 +++++++++++++++++++++++++++++++
 src/realpath.c      | 43 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 89 insertions(+), 1 deletion(-)
 create mode 100644 src/Makefile
 create mode 100644 src/bash.h
 create mode 100644 src/realpath.c

diff --git a/.gitignore b/.gitignore
index cfcaaa17..e64b0156 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,5 @@
 /versions
 /sources
 /cache
+/libexec/*.dylib
+/src/*.o
diff --git a/libexec/rbenv-hooks b/libexec/rbenv-hooks
index 86386719..939891d1 100755
--- a/libexec/rbenv-hooks
+++ b/libexec/rbenv-hooks
@@ -19,6 +19,7 @@ if [ -z "$RBENV_COMMAND" ]; then
   exit 1
 fi
 
+if ! enable -f "${BASH_SOURCE%/*}"/rbenv-realpath.dylib realpath 2>/dev/null; then
 READLINK=$(type -p greadlink readlink | head -1)
 if [ -z "$READLINK" ]; then
   echo "rbenv: cannot find readlink - are you missing GNU coreutils?" >&2
@@ -42,13 +43,14 @@ realpath() {
   echo "$(pwd)/$name"
   cd "$cwd"
 }
+fi
 
 IFS=: hook_paths=($RBENV_HOOK_PATH)
 
 shopt -s nullglob
 for path in "${hook_paths[@]}"; do
   for script in "$path/$RBENV_COMMAND"/*.bash; do
-    echo $(realpath $script)
+    realpath "$script"
   done
 done
 shopt -u nullglob
diff --git a/src/Makefile b/src/Makefile
new file mode 100644
index 00000000..3d359c0d
--- /dev/null
+++ b/src/Makefile
@@ -0,0 +1,10 @@
+SHOBJ_LDFLAGS = -dynamiclib -current_version 1.0
+
+.c.o:
+	$(CC) $(CFLAGS) -c -o $@ $<
+
+../libexec/rbenv-realpath.dylib: realpath.o
+	$(CC) $(CFLAGS) $(SHOBJ_LDFLAGS) -o $@ realpath.o
+
+clean:
+	rm -f *.o ../libexec/*.dylib
diff --git a/src/bash.h b/src/bash.h
new file mode 100644
index 00000000..1b29fd05
--- /dev/null
+++ b/src/bash.h
@@ -0,0 +1,31 @@
+#ifndef __BASH_H__
+#define __BASH_H__
+
+#define EXECUTION_SUCCESS 0
+#define EXECUTION_FAILURE 1
+#define EX_USAGE 258
+
+#define BUILTIN_ENABLED 1
+
+typedef struct word_desc {
+  char *word;
+  int flags;
+} WORD_DESC;
+
+typedef struct word_list {
+  struct word_list *next;
+  WORD_DESC *word;
+} WORD_LIST;
+
+typedef int sh_builtin_func_t(WORD_LIST *);
+
+struct builtin {
+  char *name;
+  sh_builtin_func_t *function;
+  int flags;
+  char * const *long_doc;
+  const char *short_doc;
+  char *unused;
+};
+
+#endif
diff --git a/src/realpath.c b/src/realpath.c
new file mode 100644
index 00000000..6c0c9f3c
--- /dev/null
+++ b/src/realpath.c
@@ -0,0 +1,43 @@
+#include "bash.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+int realpath_builtin(list)
+WORD_LIST *list;
+{
+	int es;
+	char *realbuf, *p;
+
+	if (list == 0) {
+		// builtin_usage();
+		return (EX_USAGE);
+	}
+
+	for (es = EXECUTION_SUCCESS; list; list = list->next) {
+		p = list->word->word;
+		realbuf = realpath(p, NULL);
+		if (realbuf == NULL) {
+			es = EXECUTION_FAILURE;
+			// builtin_error("%s: cannot resolve: %s", p, strerror(errno));
+		} else {
+			printf("%s\n", realbuf);
+			free(realbuf);
+		}
+	}
+	return es;
+}
+
+char *realpath_doc[] = {
+	"Display each PATHNAME argument, resolving symbolic links. The exit status",
+	"is 0 if each PATHNAME was resolved; non-zero otherwise.",
+	(char *)NULL
+};
+
+struct builtin realpath_struct = {
+	"realpath",
+	realpath_builtin,
+	BUILTIN_ENABLED,
+	realpath_doc,
+	"realpath pathname [pathname...]",
+	0
+};

From 284588f9b4769297c8affa5419ec2e6f59047c4b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sat, 4 Jan 2014 16:32:54 +0100
Subject: [PATCH 02/11] Fix hooks tests on OS X by expanding BATS_TMPDIR

With `realpath` extension, hooks tests on OS X will output
`/private/tmp` instead of `/tmp` because the latter is an actual symlink
to the former.

Avoid this mistmach in output assertions by expanding BATS_TMPDIR if
`realpath` extension is compiled.
---
 test/test_helper.bash | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/test/test_helper.bash b/test/test_helper.bash
index 53ae8e64..1f772bea 100644
--- a/test/test_helper.bash
+++ b/test/test_helper.bash
@@ -1,7 +1,11 @@
 unset RBENV_VERSION
 unset RBENV_DIR
 
-RBENV_TEST_DIR="${BATS_TMPDIR}/rbenv"
+if enable -f "${BATS_TEST_DIRNAME}"/../libexec/rbenv-realpath.dylib realpath 2>/dev/null; then
+  RBENV_TEST_DIR="$(realpath "$BATS_TMPDIR")/rbenv"
+else
+  RBENV_TEST_DIR="${BATS_TMPDIR}/rbenv"
+fi
 
 # guard against executing this block twice due to bats internals
 if [ "$RBENV_ROOT" != "${RBENV_TEST_DIR}/root" ]; then

From 5287e2ebf46b8636af653c1c61d4dc0dffd65796 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sat, 4 Jan 2014 16:36:02 +0100
Subject: [PATCH 03/11] Avoid slow `abs_dirname()` by loading `realpath`
 extension

This speeds up every `rbenv` invocation significantly.
---
 libexec/rbenv | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libexec/rbenv b/libexec/rbenv
index 2d475857..a458c473 100755
--- a/libexec/rbenv
+++ b/libexec/rbenv
@@ -12,6 +12,12 @@ if [ -n "$RBENV_DEBUG" ]; then
   set -x
 fi
 
+if enable -f "${0%/*}"/../libexec/rbenv-realpath.dylib realpath 2>/dev/null; then
+  abs_dirname() {
+    local path="$(realpath "$1")"
+    echo "${path%/*}"
+  }
+else
 READLINK=$(type -p greadlink readlink | head -1)
 if [ -z "$READLINK" ]; then
   echo "rbenv: cannot find readlink - are you missing GNU coreutils?" >&2
@@ -35,6 +41,7 @@ abs_dirname() {
   pwd
   cd "$cwd"
 }
+fi
 
 if [ -z "${RBENV_ROOT}" ]; then
   RBENV_ROOT="${HOME}/.rbenv"

From 8bac95899491cc043a40b274be224236a8224483 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sat, 4 Jan 2014 16:37:20 +0100
Subject: [PATCH 04/11] Stop using `abs_dirname()` in rbenv-init

It's slow and not necessary since we expect `$0` to already be expanded.

In tests this change forces us to deal with some relative paths, but
it's not a big deal. The `rbenv init -` output in the most common case
will be the same as before:

    source '/home/myuser/.rbenv/libexec/../completions/rbenv.bash'
---
 libexec/rbenv-init | 26 +-------------------------
 test/init.bats     |  4 ++--
 2 files changed, 3 insertions(+), 27 deletions(-)

diff --git a/libexec/rbenv-init b/libexec/rbenv-init
index 5f9079a7..8718c116 100755
--- a/libexec/rbenv-init
+++ b/libexec/rbenv-init
@@ -28,31 +28,7 @@ if [ -z "$shell" ]; then
   shell="$(basename "${shell:-$SHELL}")"
 fi
 
-READLINK=$(type -p greadlink readlink | head -1)
-if [ -z "$READLINK" ]; then
-  echo "rbenv: cannot find readlink - are you missing GNU coreutils?" >&2
-  exit 1
-fi
-
-resolve_link() {
-  $READLINK "$1"
-}
-
-abs_dirname() {
-  local cwd="$(pwd)"
-  local path="$1"
-
-  while [ -n "$path" ]; do
-    cd "${path%/*}"
-    local name="${path##*/}"
-    path="$(resolve_link "$name" || true)"
-  done
-
-  pwd
-  cd "$cwd"
-}
-
-root="$(abs_dirname "$0")/.."
+root="${0%/*}/.."
 
 if [ -z "$print" ]; then
   case "$shell" in
diff --git a/test/init.bats b/test/init.bats
index aa50f091..2587a014 100644
--- a/test/init.bats
+++ b/test/init.bats
@@ -21,7 +21,7 @@ load test_helper
   root="$(cd $BATS_TEST_DIRNAME/.. && pwd)"
   run rbenv-init - bash
   assert_success
-  assert_line "source '${root}/libexec/../completions/rbenv.bash'"
+  assert_line "source '${root}/test/../libexec/../completions/rbenv.bash'"
 }
 
 @test "detect parent shell" {
@@ -35,7 +35,7 @@ load test_helper
   root="$(cd $BATS_TEST_DIRNAME/.. && pwd)"
   run rbenv-init - fish
   assert_success
-  assert_line ". '${root}/libexec/../completions/rbenv.fish'"
+  assert_line ". '${root}/test/../libexec/../completions/rbenv.fish'"
 }
 
 @test "fish instructions" {

From 68b92a7f5d408b57dbba195ddd3920d533f1f429 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sat, 4 Jan 2014 21:58:12 +0100
Subject: [PATCH 05/11] Test compiled native extensions on Travis CI

---
 .travis.yml | 6 ++++--
 test/run    | 8 ++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)
 create mode 100755 test/run

diff --git a/.travis.yml b/.travis.yml
index ca1abab7..95b46cc2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,6 @@
 install: git clone https://github.com/sstephenson/bats.git
-script: bats/bin/bats --tap test
-# skips unnecessary Ruby-specific setup
+script: PATH="./bats/bin:$PATH" test/run
 language: c
+env:
+  - RBENV_NATIVE_EXT=
+  - RBENV_NATIVE_EXT=1
diff --git a/test/run b/test/run
new file mode 100755
index 00000000..44f41288
--- /dev/null
+++ b/test/run
@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+set -e
+
+if [ -n "$RBENV_NATIVE_EXT" ]; then
+  make -C src
+fi
+
+exec bats ${CI:+--tap} test

From 3f74da0e73a088f1273554f8d520e893a0697d33 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sat, 4 Jan 2014 21:59:27 +0100
Subject: [PATCH 06/11] Fail hard if RBENV_NATIVE_EXT is set but extensions
 failed to load

---
 libexec/rbenv         | 4 ++++
 libexec/rbenv-hooks   | 4 ++++
 test/test_helper.bash | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/libexec/rbenv b/libexec/rbenv
index a458c473..4041df82 100755
--- a/libexec/rbenv
+++ b/libexec/rbenv
@@ -18,6 +18,10 @@ if enable -f "${0%/*}"/../libexec/rbenv-realpath.dylib realpath 2>/dev/null; the
     echo "${path%/*}"
   }
 else
+  if [ -n "$RBENV_NATIVE_EXT" ]; then
+    echo "rbenv: failed to load \`realpath' builtin" >&2
+    exit 1
+  fi
 READLINK=$(type -p greadlink readlink | head -1)
 if [ -z "$READLINK" ]; then
   echo "rbenv: cannot find readlink - are you missing GNU coreutils?" >&2
diff --git a/libexec/rbenv-hooks b/libexec/rbenv-hooks
index 939891d1..201c91da 100755
--- a/libexec/rbenv-hooks
+++ b/libexec/rbenv-hooks
@@ -20,6 +20,10 @@ if [ -z "$RBENV_COMMAND" ]; then
 fi
 
 if ! enable -f "${BASH_SOURCE%/*}"/rbenv-realpath.dylib realpath 2>/dev/null; then
+  if [ -n "$RBENV_NATIVE_EXT" ]; then
+    echo "rbenv: failed to load \`realpath' builtin" >&2
+    exit 1
+  fi
 READLINK=$(type -p greadlink readlink | head -1)
 if [ -z "$READLINK" ]; then
   echo "rbenv: cannot find readlink - are you missing GNU coreutils?" >&2
diff --git a/test/test_helper.bash b/test/test_helper.bash
index 1f772bea..461bb085 100644
--- a/test/test_helper.bash
+++ b/test/test_helper.bash
@@ -4,6 +4,10 @@ unset RBENV_DIR
 if enable -f "${BATS_TEST_DIRNAME}"/../libexec/rbenv-realpath.dylib realpath 2>/dev/null; then
   RBENV_TEST_DIR="$(realpath "$BATS_TMPDIR")/rbenv"
 else
+  if [ -n "$RBENV_NATIVE_EXT" ]; then
+    echo "rbenv: failed to load \`realpath' builtin" >&2
+    exit 1
+  fi
   RBENV_TEST_DIR="${BATS_TMPDIR}/rbenv"
 fi
 

From b5622bee3ab562dd867a1189df8551f44d36443e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sat, 4 Jan 2014 22:04:59 +0100
Subject: [PATCH 07/11] Try without `-current_version`

Seems to only work on OS X; fails on Travis
https://travis-ci.org/sstephenson/rbenv/jobs/16384866
---
 src/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Makefile b/src/Makefile
index 3d359c0d..6b31fd06 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,4 +1,4 @@
-SHOBJ_LDFLAGS = -dynamiclib -current_version 1.0
+SHOBJ_LDFLAGS = -dynamiclib
 
 .c.o:
 	$(CC) $(CFLAGS) -c -o $@ $<

From 8facb3b3a790fd275a4e8d5f4de474bbd837c040 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sun, 5 Jan 2014 17:58:07 +0100
Subject: [PATCH 08/11] Import `shobj-conf` script from bash

Given the `-o <HOST-OS>` parameter, the script generates environment
variables with information how to compile dynamically loadable libraries
for that system.

Imported from bash-3.2.48
---
 src/shobj-conf | 547 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 547 insertions(+)
 create mode 100755 src/shobj-conf

diff --git a/src/shobj-conf b/src/shobj-conf
new file mode 100755
index 00000000..ef7863a3
--- /dev/null
+++ b/src/shobj-conf
@@ -0,0 +1,547 @@
+#! /bin/sh
+#
+# shobj-conf -- output a series of variable assignments to be substituted
+#		into a Makefile by configure which specify system-dependent
+#		information for creating shared objects that may be loaded
+#		into bash with `enable -f'
+#
+# usage: shobj-conf [-C compiler] -c host_cpu -o host_os -v host_vendor
+#
+# Chet Ramey
+# chet@po.cwru.edu
+
+# Copyright (C) 1996-2002 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA.
+
+#
+# defaults
+#
+SHOBJ_STATUS=supported
+SHLIB_STATUS=supported
+
+SHOBJ_CC=cc
+SHOBJ_CFLAGS=
+SHOBJ_LD=
+SHOBJ_LDFLAGS=
+SHOBJ_XLDFLAGS=
+SHOBJ_LIBS=
+
+SHLIB_XLDFLAGS=
+SHLIB_LIBS=
+
+SHLIB_DOT='.'
+SHLIB_LIBPREF='lib'
+SHLIB_LIBSUFF='so'
+
+SHLIB_LIBVERSION='$(SHLIB_LIBSUFF)'
+SHLIB_DLLVERSION='$(SHLIB_MAJOR)'
+
+PROGNAME=`basename $0`
+USAGE="$PROGNAME [-C compiler] -c host_cpu -o host_os -v host_vendor"
+
+while [ $# -gt 0 ]; do
+	case "$1" in
+	-C)	shift; SHOBJ_CC="$1"; shift ;;
+	-c)	shift; host_cpu="$1"; shift ;;
+	-o)	shift; host_os="$1"; shift ;;
+	-v)	shift; host_vendor="$1"; shift ;;
+	*)	echo "$USAGE" >&2 ; exit 2;;
+	esac
+done
+
+case "${host_os}-${SHOBJ_CC}" in
+sunos4*-*gcc*)
+	SHOBJ_CFLAGS=-fpic
+	SHOBJ_LD=/usr/bin/ld
+	SHOBJ_LDFLAGS='-assert pure-text'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)$(SHLIB_MINOR)'
+	;;
+
+sunos4*)
+	SHOBJ_CFLAGS=-pic
+	SHOBJ_LD=/usr/bin/ld
+	SHOBJ_LDFLAGS='-assert pure-text'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)$(SHLIB_MINOR)'
+	;;
+
+sunos5*-*gcc*|solaris2*-*gcc*)
+	SHOBJ_CFLAGS=-fpic
+	SHOBJ_LD='${CC}'
+	ld_used=`gcc -print-prog-name=ld`
+	if ${ld_used} -V 2>&1 | grep GNU >/dev/null 2>&1; then
+		# This line works for the GNU ld
+		SHOBJ_LDFLAGS='-shared -Wl,-h,$@'
+	else
+		# This line works for the Solaris linker in /usr/ccs/bin/ld
+		SHOBJ_LDFLAGS='-shared -Wl,-i -Wl,-h,$@'
+	fi
+
+#	SHLIB_XLDFLAGS='-R $(libdir)'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sunos5*|solaris2*)
+	SHOBJ_CFLAGS='-K pic'
+	SHOBJ_LD=/usr/ccs/bin/ld
+	SHOBJ_LDFLAGS='-G -dy -z text -i -h $@'
+
+#	SHLIB_XLDFLAGS='-R $(libdir)'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+# All versions of Linux or the semi-mythical GNU Hurd.
+linux*-*|gnu*-*|k*bsd*-gnu-*)
+	SHOBJ_CFLAGS=-fPIC
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared -Wl,-soname,$@'
+
+	SHLIB_XLDFLAGS='-Wl,-rpath,$(libdir) -Wl,-soname,`basename $@ $(SHLIB_MINOR)`'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)$(SHLIB_MINOR)'
+	;;
+
+freebsd2* | netbsd*)
+	SHOBJ_CFLAGS=-fpic
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS='-x -Bshareable'
+
+	SHLIB_XLDFLAGS='-R$(libdir)'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)$(SHLIB_MINOR)'
+	;;
+
+# FreeBSD-3.x ELF
+freebsd[3-9]*|freebsdelf[3-9]*|freebsdaout[3-9]*|dragonfly*)
+	SHOBJ_CFLAGS=-fpic
+	SHOBJ_LD='${CC}'
+
+	if [ -x /usr/bin/objformat ] && [ "`/usr/bin/objformat`" = "elf" ]; then
+		SHOBJ_LDFLAGS='-shared -Wl,-soname,$@'
+
+		SHLIB_XLDFLAGS='-Wl,-rpath,$(libdir)'
+		SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	else
+		SHOBJ_LDFLAGS='-shared'
+
+		SHLIB_XLDFLAGS='-R$(libdir)'
+		SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)$(SHLIB_MINOR)'
+	fi
+	;;
+
+# Darwin/MacOS X
+darwin8*)
+	SHOBJ_STATUS=supported
+	SHLIB_STATUS=supported
+	
+	SHOBJ_CFLAGS='-fno-common'
+
+	SHOBJ_LD='MACOSX_DEPLOYMENT_TARGET=10.3 ${CC}'
+
+	SHLIB_LIBVERSION='$(SHLIB_MAJOR)$(SHLIB_MINOR).$(SHLIB_LIBSUFF)'
+	SHLIB_LIBSUFF='dylib'
+
+	SHOBJ_LDFLAGS='-undefined dynamic_lookup'
+	SHLIB_XLDFLAGS='-dynamiclib -arch_only `/usr/bin/arch` -install_name $(libdir)/$@ -current_version $(SHLIB_MAJOR)$(SHLIB_MINOR) -compatibility_version $(SHLIB_MAJOR) -v'
+
+	SHLIB_LIBS='-lncurses'	# see if -lcurses works on MacOS X 10.1 
+	;;
+
+darwin*|macosx*)
+	SHOBJ_STATUS=unsupported
+	SHLIB_STATUS=supported
+
+	SHOBJ_CFLAGS='-fno-common'
+
+	SHOBJ_LD='${CC}'
+
+	SHLIB_LIBVERSION='$(SHLIB_MAJOR)$(SHLIB_MINOR).$(SHLIB_LIBSUFF)'
+	SHLIB_LIBSUFF='dylib'
+
+	case "${host_os}" in
+	darwin[78]*)	SHOBJ_LDFLAGS=''
+			SHLIB_XLDFLAGS='-dynamiclib -arch_only `/usr/bin/arch` -install_name $(libdir)/$@ -current_version $(SHLIB_MAJOR)$(SHLIB_MINOR) -compatibility_version $(SHLIB_MAJOR) -v'
+			;;
+	*)		SHOBJ_LDFLAGS='-dynamic'
+			SHLIB_XLDFLAGS='-arch_only `/usr/bin/arch` -install_name $(libdir)/$@ -current_version $(SHLIB_MAJOR)$(SHLIB_MINOR) -compatibility_version $(SHLIB_MAJOR) -v'
+			;;
+	esac
+
+	SHLIB_LIBS='-lncurses'	# see if -lcurses works on MacOS X 10.1 
+	;;
+
+openbsd*)
+	SHOBJ_CFLAGS=-fPIC
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared'
+
+	SHLIB_XLDFLAGS='-R$(libdir)'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)$(SHLIB_MINOR)'
+	;;
+
+bsdi2*)
+	SHOBJ_CC=shlicc2
+	SHOBJ_CFLAGS=
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS=-r
+	SHOBJ_LIBS=-lc_s.2.1.0
+
+	# BSD/OS 2.x and 3.x `shared libraries' are too much of a pain in
+	# the ass -- they require changing {/usr/lib,etc}/shlib.map on
+	# each system, and the library creation process is byzantine
+	SHLIB_STATUS=unsupported
+	;;
+
+bsdi3*)
+	SHOBJ_CC=shlicc2
+	SHOBJ_CFLAGS=
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS=-r
+	SHOBJ_LIBS=-lc_s.3.0.0
+
+	# BSD/OS 2.x and 3.x `shared libraries' are too much of a pain in
+	# the ass -- they require changing {/usr/lib,etc}/shlib.map on
+	# each system, and the library creation process is byzantine
+	SHLIB_STATUS=unsupported
+	;;
+
+bsdi4*)
+	# BSD/OS 4.x now supports ELF and SunOS-style dynamically-linked
+	# shared libraries.  gcc 2.x is the standard compiler, and the
+	# `normal' gcc options should work as they do in Linux.
+
+	SHOBJ_CFLAGS=-fPIC
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared -Wl,-soname,$@'
+
+	SHLIB_XLDFLAGS='-Wl,-soname,`basename $@ $(SHLIB_MINOR)`'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)$(SHLIB_MINOR)'
+	;;
+
+osf*-*gcc*)
+	# Fix to use gcc linker driver from bfischer@TechFak.Uni-Bielefeld.DE
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared -Wl,-soname,$@'
+
+	SHLIB_XLDFLAGS='-rpath $(libdir)'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+osf*)
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS='-shared -soname $@ -expect_unresolved "*"'
+
+	SHLIB_XLDFLAGS='-rpath $(libdir)'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+aix4.[2-9]*-*gcc*)		# lightly tested by jik@cisco.com
+	SHOBJ_CFLAGS=-fpic
+	SHOBJ_LD='ld'
+	SHOBJ_LDFLAGS='-bdynamic -bnoentry -bexpall'
+	SHOBJ_XLDFLAGS='-G'
+
+	SHLIB_XLDFLAGS='-bM:SRE'
+	SHLIB_LIBS='-lcurses -lc'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+aix4.[2-9]*)
+	SHOBJ_CFLAGS=-K
+	SHOBJ_LD='ld'
+	SHOBJ_LDFLAGS='-bdynamic -bnoentry -bexpall'
+	SHOBJ_XLDFLAGS='-G'
+
+	SHLIB_XLDFLAGS='-bM:SRE'
+	SHLIB_LIBS='-lcurses -lc'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+#
+# THE FOLLOWING ARE UNTESTED -- and some may not support the dlopen interface
+#
+irix[56]*-*gcc*)
+	SHOBJ_CFLAGS='-fpic'
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared -Wl,-soname,$@'
+
+	SHLIB_XLDFLAGS='-Wl,-rpath,$(libdir)'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+irix[56]*)
+	SHOBJ_CFLAGS='-K PIC'
+	SHOBJ_LD=ld
+#	SHOBJ_LDFLAGS='-call_shared -hidden_symbol -no_unresolved -soname $@'
+#	Change from David Kaelbling <drk@sgi.com>.  If you have problems,
+#	remove the `-no_unresolved'
+	SHOBJ_LDFLAGS='-shared -no_unresolved -soname $@'
+
+	SHLIB_XLDFLAGS='-rpath $(libdir)'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+hpux9*-*gcc*)
+	# must use gcc; the bundled cc cannot compile PIC code
+	SHOBJ_CFLAGS='-fpic'
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared -Wl,-b -Wl,+s'
+
+	SHLIB_XLDFLAGS='-Wl,+b,$(libdir)'
+	SHLIB_LIBSUFF='sl'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+hpux9*)
+	SHOBJ_STATUS=unsupported
+	SHLIB_STATUS=unsupported
+
+	# If you are using the HP ANSI C compiler, you can uncomment and use
+	# this code (I have not tested it)
+#	SHOBJ_STATUS=supported
+#	SHLIB_STATUS=supported
+#
+#	SHOBJ_CFLAGS='+z'
+#	SHOBJ_LD='ld'
+#	SHOBJ_LDFLAGS='-b +s'
+#
+#	SHLIB_XLDFLAGS='+b $(libdir)'
+#	SHLIB_LIBSUFF='sl'
+#	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'	
+
+	;;
+
+hpux10*-*gcc*)
+	# must use gcc; the bundled cc cannot compile PIC code
+	SHOBJ_CFLAGS='-fpic'
+	SHOBJ_LD='${CC}'
+	# if you have problems linking here, moving the `-Wl,+h,$@' from
+	# SHLIB_XLDFLAGS to SHOBJ_LDFLAGS has been reported to work
+	SHOBJ_LDFLAGS='-shared -Wl,-b -Wl,+s'
+
+	SHLIB_XLDFLAGS='-Wl,+h,$@ -Wl,+b,$(libdir)'
+	SHLIB_LIBSUFF='sl'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+hpux10*)
+	SHOBJ_STATUS=unsupported
+	SHLIB_STATUS=unsupported
+
+	# If you are using the HP ANSI C compiler, you can uncomment and use
+	# this code (I have not tested it)
+#	SHOBJ_STATUS=supported
+#	SHLIB_STATUS=supported
+#
+#	SHOBJ_CFLAGS='+z'
+#	SHOBJ_LD='ld'
+#	SHOBJ_LDFLAGS='-b +s +h $@'
+#
+#	SHLIB_XLDFLAGS='+b $(libdir)'
+#	SHLIB_LIBSUFF='sl'
+#	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'	
+
+	;;
+
+hpux11*-*gcc*)
+	# must use gcc; the bundled cc cannot compile PIC code
+	SHOBJ_CFLAGS='-fpic'
+	SHOBJ_LD='${CC}'
+#	SHOBJ_LDFLAGS='-shared -Wl,-b -Wl,-B,symbolic -Wl,+s -Wl,+std -Wl,+h,$@'
+	SHOBJ_LDFLAGS='-shared -fpic -Wl,-b -Wl,+s -Wl,+h,$@'
+
+	SHLIB_XLDFLAGS='-Wl,+b,$(libdir)'
+	SHLIB_LIBSUFF='sl'
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+hpux11*)
+	SHOBJ_STATUS=unsupported
+	SHLIB_STATUS=unsupported
+
+	# If you are using the HP ANSI C compiler, you can uncomment and use
+	# this code (I have not tested it)
+#	SHOBJ_STATUS=supported
+#	SHLIB_STATUS=supported
+#
+#	SHOBJ_CFLAGS='+z'
+#	SHOBJ_LD='ld'
+#	SHOBJ_LDFLAGS='-b +s +h $@'
+#
+#	SHLIB_XLDFLAGS='+b $(libdir)'
+#	SHLIB_LIBSUFF='sl'
+#	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'	
+
+	;;
+
+sysv4*-*gcc*)
+	SHOBJ_CFLAGS=-shared
+	SHOBJ_LDFLAGS='-shared -h $@'
+	SHOBJ_LD='${CC}'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sysv4*)
+	SHOBJ_CFLAGS='-K PIC'
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS='-dy -z text -G -h $@'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sco3.2v5*-*gcc*)
+	SHOBJ_CFLAGS='-fpic'		# DEFAULTS TO ELF
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sco3.2v5*)
+	SHOBJ_CFLAGS='-K pic -b elf'
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS='-G -b elf -dy -z text -h $@'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sysv5uw7*-*gcc*)
+	SHOBJ_CFLAGS='-fpic'
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sysv5uw7*)
+	SHOBJ_CFLAGS='-K PIC'
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS='-G -dy -z text -h $@'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sysv5UnixWare*-*gcc*)
+	SHOBJ_CFLAGS=-fpic
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sysv5UnixWare*)
+	SHOBJ_CFLAGS='-K PIC'
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS='-G -dy -z text -h $@'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sysv5OpenUNIX*-*gcc*)
+	SHOBJ_CFLAGS=-fpic
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+sysv5OpenUNIX*)
+	SHOBJ_CFLAGS='-K PIC'
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS='-G -dy -z text -h $@'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+dgux*-*gcc*)
+	SHOBJ_CFLAGS=-fpic
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+dgux*)
+	SHOBJ_CFLAGS='-K pic'
+	SHOBJ_LD=ld
+	SHOBJ_LDFLAGS='-G -dy -h $@'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+msdos*)
+	SHOBJ_STATUS=unsupported
+	SHLIB_STATUS=unsupported
+	;;
+
+cygwin*)
+	SHOBJ_LD='$(CC)'
+        SHOBJ_LDFLAGS='-shared -Wl,--enable-auto-import -Wl,--enable-auto-image-base -Wl,--export-all -Wl,--out-implib=$(@).a'
+        SHLIB_LIBPREF='cyg'
+        SHLIB_LIBSUFF='dll'
+        SHLIB_LIBVERSION='$(SHLIB_DLLVERSION).$(SHLIB_LIBSUFF)'
+        SHLIB_LIBS='$(TERMCAP_LIB)'
+
+	SHLIB_DOT=
+        # For official cygwin releases, DLLVERSION will be defined in the
+        # environment of configure, and will be incremented any time the API
+        # changes in a non-backwards compatible manner.  Otherwise, it is just
+        # SHLIB_MAJOR.
+        if [ -n "$DLLVERSION" ] ; then
+		SHLIB_DLLVERSION="$DLLVERSION"
+        fi
+	;;
+
+#
+# Rely on correct gcc configuration for everything else
+#
+*-*gcc*)
+	SHOBJ_CFLAGS=-fpic
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-shared'
+
+	SHLIB_LIBVERSION='$(SHLIB_LIBSUFF).$(SHLIB_MAJOR)'
+	;;
+
+*)
+	SHOBJ_STATUS=unsupported
+	SHLIB_STATUS=unsupported
+	;;
+
+esac
+
+echo SHOBJ_CC=\'"$SHOBJ_CC"\'
+echo SHOBJ_CFLAGS=\'"$SHOBJ_CFLAGS"\'
+echo SHOBJ_LD=\'"$SHOBJ_LD"\'
+echo SHOBJ_LDFLAGS=\'"$SHOBJ_LDFLAGS"\'
+echo SHOBJ_XLDFLAGS=\'"$SHOBJ_XLDFLAGS"\'
+echo SHOBJ_LIBS=\'"$SHOBJ_LIBS"\'
+
+echo SHLIB_XLDFLAGS=\'"$SHLIB_XLDFLAGS"\'
+echo SHLIB_LIBS=\'"$SHLIB_LIBS"\'
+
+echo SHLIB_DOT=\'"$SHLIB_DOT"\'
+
+echo SHLIB_LIBPREF=\'"$SHLIB_LIBPREF"\'
+echo SHLIB_LIBSUFF=\'"$SHLIB_LIBSUFF"\'
+
+echo SHLIB_LIBVERSION=\'"$SHLIB_LIBVERSION"\'
+echo SHLIB_DLLVERSION=\'"$SHLIB_DLLVERSION"\'
+
+echo SHOBJ_STATUS=\'"$SHOBJ_STATUS"\'
+echo SHLIB_STATUS=\'"$SHLIB_STATUS"\'
+
+exit 0

From 302b317b895777cbf8a322b3362a17005131ae48 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sun, 5 Jan 2014 18:00:31 +0100
Subject: [PATCH 09/11] Fix `shobj-conf` on Darwin

The `shobj-conf` script imported from bash seems to not support the
latest OS X. This makes sure that `SHOBJ_LDFLAG=-dynamiclib` is output
for Darwin10+ (latest version is Darwin 13.0).
---
 src/shobj-conf | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/shobj-conf b/src/shobj-conf
index ef7863a3..593867ee 100755
--- a/src/shobj-conf
+++ b/src/shobj-conf
@@ -142,6 +142,17 @@ freebsd[3-9]*|freebsdelf[3-9]*|freebsdaout[3-9]*|dragonfly*)
 	;;
 
 # Darwin/MacOS X
+darwin1*)
+	SHOBJ_STATUS=supported
+	SHLIB_STATUS=supported
+	
+	SHOBJ_CFLAGS=''
+	SHLIB_LIBSUFF='dylib'
+
+	SHOBJ_LD='${CC}'
+	SHOBJ_LDFLAGS='-dynamiclib'
+	;;
+
 darwin8*)
 	SHOBJ_STATUS=supported
 	SHLIB_STATUS=supported

From a6e0785b84993fa3a5192a66ee816ed7c0e0a43e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sun, 5 Jan 2014 17:55:43 +0100
Subject: [PATCH 10/11] Create `configure` script to generate a cross-platform
 Makefile

The previous Makefile only worked on OS X. The dynamically generated
Makefile (from `Makefile.in`) should now work on multiple platforms
(tested on OS X and Ubuntu).
---
 .gitignore      |  1 +
 src/Makefile    | 10 ----------
 src/Makefile.in | 25 +++++++++++++++++++++++++
 src/configure   | 39 +++++++++++++++++++++++++++++++++++++++
 test/run        |  1 +
 5 files changed, 66 insertions(+), 10 deletions(-)
 delete mode 100644 src/Makefile
 create mode 100644 src/Makefile.in
 create mode 100755 src/configure

diff --git a/.gitignore b/.gitignore
index e64b0156..84639e79 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,4 +5,5 @@
 /sources
 /cache
 /libexec/*.dylib
+/src/Makefile
 /src/*.o
diff --git a/src/Makefile b/src/Makefile
deleted file mode 100644
index 6b31fd06..00000000
--- a/src/Makefile
+++ /dev/null
@@ -1,10 +0,0 @@
-SHOBJ_LDFLAGS = -dynamiclib
-
-.c.o:
-	$(CC) $(CFLAGS) -c -o $@ $<
-
-../libexec/rbenv-realpath.dylib: realpath.o
-	$(CC) $(CFLAGS) $(SHOBJ_LDFLAGS) -o $@ realpath.o
-
-clean:
-	rm -f *.o ../libexec/*.dylib
diff --git a/src/Makefile.in b/src/Makefile.in
new file mode 100644
index 00000000..b4b1825b
--- /dev/null
+++ b/src/Makefile.in
@@ -0,0 +1,25 @@
+CC = @CC@
+
+CFLAGS = @CFLAGS@
+LOCAL_CFLAGS = @LOCAL_CFLAGS@
+DEFS = @DEFS@
+LOCAL_DEFS = @LOCAL_DEFS@
+
+CCFLAGS = $(DEFS) $(LOCAL_DEFS) $(LOCAL_CFLAGS) $(CFLAGS)
+
+SHOBJ_CC = @SHOBJ_CC@
+SHOBJ_CFLAGS = @SHOBJ_CFLAGS@
+SHOBJ_LD = @SHOBJ_LD@
+SHOBJ_LDFLAGS = @SHOBJ_LDFLAGS@
+SHOBJ_XLDFLAGS = @SHOBJ_XLDFLAGS@
+SHOBJ_LIBS = @SHOBJ_LIBS@
+SHOBJ_STATUS = @SHOBJ_STATUS@
+
+.c.o:
+	$(SHOBJ_CC) $(SHOBJ_CFLAGS) $(CCFLAGS) -c -o $@ $<
+
+../libexec/rbenv-realpath.dylib: realpath.o
+	$(SHOBJ_LD) $(SHOBJ_LDFLAGS) $(SHOBJ_XLDFLAGS) -o $@ realpath.o $(SHOBJ_LIBS)
+
+clean:
+	rm -f *.o ../libexec/*.dylib
diff --git a/src/configure b/src/configure
new file mode 100755
index 00000000..f54f09d2
--- /dev/null
+++ b/src/configure
@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+set -e
+
+src_dir="${0%/*}"
+
+CC="${CC:-gcc}"
+
+if ! which "$CC" &>/dev/null; then
+  echo "no compiler found: $CC" >&2
+  exit 1
+fi
+
+case "$(uname -s)" in
+Darwin* )
+  host_os="darwin$(uname -r)"
+  ;;
+OpenBSD* )
+  host_os="openbsd$(uname -r)"
+  ;;
+* )
+  host_os="linux-gnu"
+esac
+
+eval "$("$src_dir"/shobj-conf -C "$CC" -o "$host_os")"
+
+sed "
+  s,@CC@,${CC},
+  s,@CFLAGS@,${CFLAGS},
+  s,@LOCAL_CFLAGS@,${LOCAL_CFLAGS},
+  s,@DEFS@,${DEFS},
+  s,@LOCAL_DEFS@,${LOCAL_DEFS},
+  s,@SHOBJ_CC@,${SHOBJ_CC},
+  s,@SHOBJ_CFLAGS@,${SHOBJ_CFLAGS},
+  s,@SHOBJ_LD@,${SHOBJ_LD},
+  s,@SHOBJ_LDFLAGS@,${SHOBJ_LDFLAGS//,/\,},
+  s,@SHOBJ_XLDFLAGS@,${SHOBJ_XLDFLAGS//,/\,},
+  s,@SHOBJ_LIBS@,${SHOBJ_LIBS},
+  s,@SHOBJ_STATUS@,${SHOBJ_STATUS},
+" "$src_dir"/Makefile.in > "$src_dir"/Makefile
diff --git a/test/run b/test/run
index 44f41288..9d3b9e52 100755
--- a/test/run
+++ b/test/run
@@ -2,6 +2,7 @@
 set -e
 
 if [ -n "$RBENV_NATIVE_EXT" ]; then
+  src/configure
   make -C src
 fi
 

From 294cff3fd4a2d6bfbabf91591383f99715144d11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <mislav.marohnic@gmail.com>
Date: Sun, 5 Jan 2014 18:27:35 +0100
Subject: [PATCH 11/11] Fall back to `cc` as default compiler when `gcc` is not
 available

---
 src/configure | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/configure b/src/configure
index f54f09d2..dc29eb79 100755
--- a/src/configure
+++ b/src/configure
@@ -3,10 +3,17 @@ set -e
 
 src_dir="${0%/*}"
 
-CC="${CC:-gcc}"
+if [ -z "$CC" ]; then
+  if type -p gcc >/dev/null; then
+    CC=gcc
+  else
+    echo "warning: gcc not found; using CC=cc" >&2
+    CC=cc
+  fi
+fi
 
-if ! which "$CC" &>/dev/null; then
-  echo "no compiler found: $CC" >&2
+if ! type -p "$CC" >/dev/null; then
+  echo "aborted: compiler not found: $CC" >&2
   exit 1
 fi