Fixed SET_SOURCE_FILES_PROPERTIES in CMakefile for wxWidgets test app.

CMakeLists.txt

@@ -352,7 +352,7 @@ IF(PHYSFS_BUILD_WX_TEST)
     IF(wxWidgets_FOUND)
         INCLUDE(${wxWidgets_USE_FILE})
         ADD_EXECUTABLE(wxtest_physfs test/wxtest_physfs.cpp)
-        SET_SOURCE_FILES_PROPERTIES(test/wxtest_physfs.cpp COMPILE_FLAGS ${wxWidgets_CXX_FLAGS})
+        SET_SOURCE_FILES_PROPERTIES(test/wxtest_physfs.cpp PROPERTIES COMPILE_FLAGS "${wxWidgets_CXX_FLAGS}")
         TARGET_LINK_LIBRARIES(wxtest_physfs ${PHYSFS_LIB_TARGET} ${wxWidgets_LIBRARIES} ${OTHER_LDFLAGS})
         SET(PHYSFS_INSTALL_TARGETS ${PHYSFS_INSTALL_TARGETS} ";wxtest_physfs")
     ELSE(wxWidgets_FOUND)