Some adjustments I had to make to build Retro68 on WSL

[frogsquire]

Hi there,

I recently got Retro68 building using Ubuntu 18.04 and cmake 3.22 on Windows Subsystem for Linux. I haven't tested the resulting programs much yet, but I wanted to share the steps I had to take to get the build working, in case it is helpful to others, or I've exposed bugs which might be fixed in a PR. Specifically, I had to make a couple of code changes to gcc:

• calls.c line 4095, machine_mode instead of auto as the type for the variable declared on that line.
• convertobj.cc line 244, move auto variable declaration out of the if block and onto its own line
• Same on convertobj.cc line 535

Also note that if you run the build script more than once, and it failed after running interfaces-and-libraries.sh, that script will fail because the strings.h file it seeks to rename has already been renamed.

Finally, as I noted in another ticket, the version of cmake that came with Ubuntu 18.04 is too old - it needs list(TRANSFORM) as a supported operation.

I hope this is helpful. Please let me know if there are further steps I should take on any of these things.

Thanks!