fix missing backslashes in paths on Windows According to https://docs.microsoft.com/fr-fr/windows/win32/fileio/naming-a-file backslashes (with slashes) are a path separator, hence must no be considered as an escape code. The first fix, in argvsplit.c, disables this. But because of fragment_quote(), the backslashes are doubled. Hence the second fix in fragment.c With this pc file : prefix=C:/Documents/msys2/opt/efl_64 libdir=${prefix}/lib includedir=${prefix}/include Name: eina Description: efl: eina Version: 1.24.99 Requires.private: iconv Libs: -L${libdir} -leina -pthread -levil Libs.private: -lpsapi -lole32 -lws2_32 -lsecur32 -luuid -lregex -lm Cflags:-I${includedir}/eina-1 -I${includedir}/efl-1 -I${includedir}/eina-1/eina -pthread pkgconf.exe --cflags eina returns : -IC:\Documents\msys2\opt\efl_64/include/eina-1 -IC:\Documents\msys2\opt\efl_64/include/efl-1 -IC:\Documents\msys2\opt\efl_64/include/eina-1/eina -pthread -DWINICONV_CONST= -IC:\Documents\msys2\opt\ewpi_64/include