[tlbuild] Issues with msys2: failed to link with -lgs, _mkdir not declared, ...

[Karl Berry]

    ../../../source/texk/dvisvgm/configure: line 21927: test: : integer
    expression expected
    checking Ghostscript version... ""
    ../../../source/texk/dvisvgm/configure: line 22046: test: : integer
    expression expected

I think I've fixed those simple syntax things. Thanks.

    < ./luatry: (command line):1: test
    ---
    > C:\msys32\home\me\texlive\Build\build\libs\lua53\luatry.exe: (command line):1: test

Evidently merely a difference in argv[0] handling.

No particular ideas about the slew of other errors, which look real :(.  -k