151d75b breaks mingw builds on Windows

[jonforums]

It appears that the fix for #459 to solve a Win 7 SDK build warning breaks the CMake/MSYS/MinGW build on my Win7 32bit system.

Note that no MinGW compiler defines _MSC_VER. Was the original _MVC_VER a typo and replacing with _MSC_VER suppress the warning? Double check cl predefined macros

C:\Users\Jon\Documents\RubyDev\mruby-git\build>git log -1 --oneline
2dbd6fa Merge pull request #462 from bovi/test-for-460

C:\Users\Jon\Documents\RubyDev\mruby-git\build>cmake -G "MSYS Makefiles" .. && make all test
...
[ 77%] Building C object src/CMakeFiles/mruby_object.dir/time.c.obj
c:/Users/Jon/Documents/RubyDev/mruby-git/src/time.c: In function 'mrb_time_update_datetime':
c:/Users/Jon/Documents/RubyDev/mruby-git/src/time.c:139:5: error: implicit declaration of
function 'gmtime_s' [-Werror=implicit-function-declaration]
c:/Users/Jon/Documents/RubyDev/mruby-git/src/time.c:142:5: error: implicit declaration of
function 'localtime_s' [-Werror=implicit-function-declaration]
cc1.exe: some warnings being treated as errors

make[2]: *** [src/CMakeFiles/mruby_object.dir/time.c.obj] Error 1
make[1]: *** [src/CMakeFiles/mruby_object.dir/all] Error 2
make: *** [all] Error 2

I'm swamped with work and will not have time to look into this for awhile, but there should be other ways to suppress warnings for cl and friends. For example, I originally supressed MSVC warning via CMake here

Please revert 151d75b and investigate using _MSC_VER or the CMake alternative.

For those of you building/testing mruby on Windows, I request that you ensure any patches work with for both MSVC and MinGW (I test with multiple MinGW versions and Win7 SDK cmd line tools).

If you don't have a MSYS/MinGW toolchain, download one of DevKit flavors I maintain at TheCodeShop. It's as simple as running the devkitvars.bat (or devkitvars.ps1) scripts which bring sh, make, gcc and friends onto your PATH. And then it's just a cd build && cmake -G "MSYS Makefiles" .. && make all test away to ensure your patch works with a MinGW toolchain.

[jonforums]

Fixing the typo from _MVC_VER to _MSC_VER appears to fix the issue on my Win7 32bit system in the following build configurations:

• mingw 4.6.2 + msys makefiles
• mingw-w64 4.7.1 + ninja build files
• win7 sdk + nmake makefiles

@shancat does using _MSC_VER also work for you?

[ghost]

My fault sorry. I don't have MinGW and I can't install it as I live in a
outlying area and all I get is 2GB of Dodo mobile broadband. I'm testing your
suggesting fix now. I was wondering why _MVC_VER didn't work in that one place
but worked every where else (I assumed).

Works with Windows 7 SDK + NMake makefiles with me.
I'll try and be more carefull with MinGW next time.

Does #465 fix it for you?

[jonforums]

@shancat it's fixed in the same environments I previously mentioned; thank you.

FWIW, it can be tricky to get code working correctly with both MSVC and the different flavors (mingw.org and mingw-w64) of MinGW due mainly to header differences. Here's hoping you can cajole a friend to download all my DevKit flavors and burn you a CD/DVD 😸