How can I convert *nix style paths into Windows style paths in CMake?

I'm developing a C program based on GLib and OpenBLAS. I hope it'd run on both Windows and linux platforms, so I chose CMake to configure the project. Here's my CMakeLists.txt:

# ...
find_package(PkgConfig REQUIRED)
pkg_check_modules(GLib REQUIRED glib-2.0)
message(STATUS "GLib Found:")
message(STATUS "  GLib include directories:   ${GLib_INCLUDE_DIRS}")
message(STATUS "  GLib library directories:   ${GLib_LIBRARY_DIRS}")
message(STATUS "  GLib libraries:             ${GLib_LIBRARIES}")
pkg_check_modules(BLAS REQUIRED openblas)
message(STATUS "OpenBLAS Found:")
message(STATUS "  BLAS include directories:   ${BLAS_INCLUDE_DIRS}")
message(STATUS "  BLAS library directories:   ${BLAS_LIBRARY_DIRS}")
message(STATUS "  BLAS libraries:             ${BLAS_LIBRARIES}")
#...

Running on MSYS2/MinGW64, cmake gives:

-- GLib Found:
--   GLib include directories:   X:/path/to/msys64/mingw64/include/glib-2.0;X:/path/to/msys64/mingw64/lib/glib-2.0/include;X:/path/to/msys64/mingw64/include
--   GLib library directories:   X:/path/to/msys64/mingw64/lib
--   GLib libraries:             glib-2.0;intl
-- OpenBLAS Found:
--   BLAS include directories:   /mingw64/include/OpenBLAS
--   BLAS library directories:   
--   BLAS libraries:             openblas

It seems that pkg-config uses *nix path on openblas which leads to include failures.

Add X:/path/to/msys64 as a prefix should work. However msys could be installed in various places and I don't know how to find the msys path in cmake.

Thanks for any help in advance.

P.S. FindBLAS gives the same output.

Solution

If you install Openblas and Glib in msys2, then you can compare the pkg-config files openblas.pc and glib-2.0.pc. Now you would figure out the differences between them. In other words, please add the prefix=/mingw64 to the openblas.pc.