#951 broke building for x86_64-pc-windows-gnu and i686-pc-windows-gnu

[jrb0001]

Output at the end:

C:/PROGRA~1/MINGW-~1/X86_64~1.0-P/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: cannot find -lvcruntime
collect2.exe: error: ld returned 1 exit status
mingw32-make.exe[2]: *** [CMakeFiles\SDL2.dir\build.make:2365: SDL2.dll] Error 1
mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:105: CMakeFiles/SDL2.dir/all] Error 2
mingw32-make.exe: *** [Makefile:129: all] Error 2
thread 'main' panicked at '
command did not execute successfully, got: exit code: 2

build script failed, must exit now', C:\Users\jrb0001\.cargo\registry\src\jackfan.us.kg-1ecc6299db9ec823\cmake-0.1.42\src\lib.rs:861:5

It looks like the patching infrastructure needs to be extended for target specific patches or is there a better way?

[Cobrand]

I think there was a mistake in #951, the vcruntime flag should only be used in the VC toolchain and not the mingw one. You're using mingw, so you got an error there because it couldn't get the lib from the msvc toolcahin.

Basically we need to differentiate between those two and apply the correct flags in both cases, just as you said. It's a very simple PR to make, do you think you'd be able to do it?