如何使CMake find_file在MSYS2上接受UNIX样式的路径？

Question

I'm using CMake 3.4.1, on Windows 10, with MSYS2 (everything up-to-date as of Dec. 25 2015).

When I use CMake's find_file command, it won't work unless the path is in Windows-style. This is a problem for me, because I'm trying to use findwxWidgets.cmake , which fails because of this.

For example:

CMakeLists.txt:

cmake_minimum_required(VERSION 3.0)
find_file(version_h version.h PATHS /mingw64/include/wx-3.0/wx)
message(STATUS "version_h: ${version_h}")

Running cmake spits out:

-- version_h: version_h-NOTFOUND

But it's clearly in there:

>>> file /mingw64/include/wx-3.0/wx/version.h
/mingw64/include/wx-3.0/wx/version.h: C source, ASCII text

I'm wondering if this is a bug, or if there's some obscure flag I have to set to get this to work. How do I get CMake's find_file to find files with UNIX-style paths?

Answer 1

MinGW-w64 cmake can't understand MSYS2 paths. You might propose a path transformation test program to the CMake developers, but that's fairly gross and I'd hope the would reject that. Instead these things must be solved case-by-case. wx-config, being a shell script, is providing an MSYS2 path.

This is a bug in the currently release MSYS2 wxWidgets packages that will be fixed in the next release. To work around it, find the line in /mingw64/bin/wx-config or /mingw32/bin/wx-config:

prefix=${input_option_prefix-${this_prefix:-/mingw64}}

(or /mingw32 of course) and add after it:

if [ "x${MSYSTEM}" = "xMINGW32" ] || [ "x${MSYSTEM}" = "xMINGW64" ]; then
    prefix=$(cygpath -m ${prefix})
fi

Be careful to remove it at upgrade time though.