Build error with MinGW (Mingw-w64) due to missing Windows.h (with capital W)

[jrosdahl]

Description

After PR #336 it's no longer possible to use doctest for Win32 cross-compilation using e.g. Mingw-w64 on a case sensitive file system.

Steps to reproduce

On a Linux system (I'm currently using Ubuntu 19.10):

1. git clone https://github.com/onqtam/doctest.git
2. cd doctest
3. printf '#define DOCTEST_CONFIG_IMPLEMENT\n#include "doctest/doctest.h"\n' >test.cpp
4. i686-w64-mingw32-g++-posix -c test.cpp
5. Watch the following output:

doctest/doctest.h:2766:10: fatal error: Windows.h: No such file or directory
 2766 | #include <Windows.h>
      |          ^~~~~~~~~~~
compilation terminated.

Using the lowercase version of windows.h works:

1. sed -i 's/Windows\.h/windows.h/' doctest/doctest.h
2. i686-w64-mingw32-g++-posix -c test.cpp && echo success (prints success)

Extra information

• doctest version: v2.3.7 or latest master (932a2ca at the time of writing)
• Operating System: Ubuntu 19.10
• Compiler+version: i686-w64-mingw32-g++-posix (GCC) 9.2-posix 20191008

Maybe of interest:

• "Lowercase windows.h and uppercase Windows.h difference?" answer on Stack Overflow.
• Catch2 uses the lowercase version.

[onqtam]

Oh gosh...... I'll fix this in the coming days - I hope I don't ever forget that and switch it back because of "compiler warnings"...

Thanks for reporting!

[onqtam]

pushed in the dev branch

[u3shit]

Okay, I think I've also got hit by this change. The only problem is that I use clang so I don't have those fancy mingw defines. Why can't we just use the lowercase windows.h always? Even microsoft itself isn't consistent about the casing of this file.

[onqtam]

@u3shit Just pushed a fix in the dev branch - always using lowercase and no ifdefs (along with silencing the Wnonportable-system-include-path warning for clang which was the reason for the capital W) - will probably release an official version in master by the end of the month.

[u3shit]

@onqtam checked it, it fixes the issue for me 👍