I was suprised and gratified when a number of people took the source code and added support for other synthesizers. I've never really worked on it much after the initial release, but over the years I have added support for the Waldorf Microwave, and ported it to Windows (retaining it's original termcap-based display - sorry!).
You can download glib4.zip, a zip file containing the most recent Windows version. This includes a pre-compiled executable with support for the TX81Z, DW8000, and Microwave. To use, just unzip the glib4.zip file, and execute glib.exe. This executable runs under Windows 95. You might have to recompile it to run under Windows 3.1.
If you want the collection of glib source code that has the support for the most number of synths, you can find it in glib2_tar.gz, which is a gzip-compressed tar file with the source code (no executables). Beware, this software is, in this day and age, an embarrassing hodge podge. It may be useful if you are looking for example code that does MIDI stuff or which manipulates the patches for a particular synthesizer.