Visual C++ 1.1 is released for Windows NT 3.1 in late 1993. This dinosaur recognized Windows 95 as Windows 3.x+Win32s, however the compiler and linker (not sure about the debugger) worked under Win95.
I've built the new development source of Mini vMac in that ancient Win32 IDE.
Problems:
1. shlobj.h and all SH* APIs are not available.
2. A LOT of Win32 constant macros are not available.
3. No OLE2 and COM headers so EnableShellLinks must be 0.
4. The third argument of waveOutOpen is required to be LPWAVEFORMAT instead of LPWAVEFORMATEX, I cannot figure out how to make that working so I have to disable sound.
5. No __int64 support for building Mini vMac II, and porting all FPU code to use largeint.h is still too difficult for me.

And it runs under Windows NT 3.5!

when I changed that WAVEFORMATEX into a PCMWAVEFORMAT
the sound worked!

Would your build also run under Windows 3.1?

I'm using Win32 version of VC1.1 so the generated executable will NOT run under Win3.1.

Actually, given that Windows 95 is seen by the compiler as being Windows 3.1+Win32s, the finished bianry probably WOULD work on a copy of Windows 3.1 so long as the Win32s libraries were installed.

Yes, that's what I thought, too. Might be something fun to try.

I had tested that on Win32s, it cannot even properly display the "ROM not found" message! seems Win32s doesn't have proper DIB support.

It would be pretty awesome to be able to port this to Windows 3.x! Maybe as an on-the-side project or something? Hmm? I'd love to fool around with an emulator within an emulator (namely VirtualBox).

I'm going to move this over to the Mini vMac folder...