build: normalise the path to libdispatch

This fixes the embedded RPATH when Foundation is cross-compiled for
Linux or android from Windows.

Author: compnerd

CMakeLists.txt

@@ -93,6 +93,7 @@ if(FOUNDATION_ENABLE_LIBDISPATCH)
   set(libdispatch_cflags -I;${FOUNDATION_PATH_TO_LIBDISPATCH_SOURCE};-I;${FOUNDATION_PATH_TO_LIBDISPATCH_BUILD}/src/swift;-Xcc;-fblocks)
   set(libdispatch_ldflags -L;${FOUNDATION_PATH_TO_LIBDISPATCH_BUILD};-L;${FOUNDATION_PATH_TO_LIBDISPATCH_BUILD}/src;-ldispatch;-lswiftDispatch)
   if(CMAKE_SYSTEM_NAME STREQUAL Linux OR CMAKE_SYSTEM_NAME STREQUAL Android OR CMAKE_SYSTEM_NAME STREQUAL FreeBSD)
+    file(TO_CMAKE_PATH "${FOUNDATION_PATH_TO_LIBDISPATCH_BUILD}" FOUNDATION_PATH_TO_LIBDISPATCH_BUILD)
     list(APPEND libdispatch_ldflags -Xlinker;-rpath;-Xlinker;${FOUNDATION_PATH_TO_LIBDISPATCH_BUILD}/src)
   endif()
 endif()