update README

README.md

@@ -66,6 +66,8 @@ current state of the work tree.
 
 ## Installation
 
+### For all users, using root access
+
 This section guides you through installing the required dependencies, compiling
 a binary, and then installing the binary.  By default, `repo2html` installs
 into the `/usr/local/bin` directory.
@@ -76,9 +78,40 @@ into the `/usr/local/bin` directory.
 4. As root, run `make install` to copy the `repo2html` binary into the
    `/usr/local/bin` directory.
 
+### For one user, without root access
+
+If you prefer, you can compile and install without root access.
+
+1. Set the following environment variables appropriately.
+   The following will install executables at `~/bin` and chicken libraries at `~/var/lib/chicken`.
+   (Verify the location of the `CHICKEN_REPOSITORY_PATH` on your system, as it might not be `/var/lib/chicken/11`):
+
+    ```
+    export CHICKEN_INSTALL_PREFIX="$HOME"
+    export CHICKEN_REPOSITORY_PATH="$HOME"/var/lib/chicken:/var/lib/chicken/11
+    export CHICKEN_INSTALL_REPOSITORY="$HOME"/var/lib/chicken
+    ```
+
+2. Ensure you're in the `repo2html` git repository.
+3. Run `make dependencies` to install the required Chicken Scheme eggs.
+4. Run `make` to compile a static `repo2html` binary in the current directory.
+5. Run `make install` to copy the `repo2html` binary into the `~/bin` directory.
+
+<!-- FIXME this part isn't true anymore since we broke the source code up into modules.
 **Note**: If you want to use `main.scm` as the `repo2html` executable, instead
 of compiling a static binary file, then run
 `cp main.scm /usr/local/bin/repo2html` as root.
+-->
+
+### Compiling for older systems 
+
+A Dockerfile is included that will build `repo2html` using Debian 11 (bullseye) running glibc-2.31.
+The resulting binary should be compatible with systems running both old and newer versions of glibc.
+
+1. Ensure docker is installed (`sudo apt install docker.io`)
+2. Run `make compile-on-debian-11`
+
+It takes a while and downloads a lot.
 
 ## Templates