I have used Virtual Pascal for over 20 years for developing OS/2 and Win32 programs. You can download the final freeware version of Virtual Pascal (v2.1b279).
Virtual Pascal is no longer being developed. Allan Mertner, the last VP developer, provides limited support via Facebook. The source to Virtual Pascal will not be released as much of the VP compiler was written in x86 32-bit assembler which would make it very difficult to port. In my opinion, Virtual Pascal makes much smaller and faster executables for OS/2 and Win32 than Free Pascal though it is nice to have options.
You can download the DOS32 plugin for VP I used for some of my BBS utilities. Make sure you follow the installation instructions exactly. This plugin will only work with VP v2.1b279. I am not the author of this plugin nor do I offer any support for it.