Fix MEX file compilation with OpenMP

Author: mariusmuja

src/matlab/CMakeLists.txt

@@ -30,10 +30,17 @@ if(MEX_CMD AND MEXEXT_CMD)
         EXECUTE_PROCESS(COMMAND ${MEXEXT_REAL_CMD} OUTPUT_VARIABLE MEX_EXTENSION OUTPUT_STRIP_TRAILING_WHITESPACE)
         SET(MEX_FILE ${CMAKE_CURRENT_BINARY_DIR}/${MEX_NAME}.${MEX_EXTENSION})
 
+        if (WIN32)
+            set(MEX_BUILD_FLAGS "COMPFLAGS='$$COMPFLAGS ${OpenMP_CXX_FLAGS}' LINKFLAGS='$$LINKFLAGS ${OpenMP_CXX_FLAGS} ${OpenMP_EXE_LINKER_FLAGS}'")
+        else()
+            set(MEX_BUILD_FLAGS "CFLAGS='$$CFLAGS ${OpenMP_CXX_FLAGS}' LDFLAGS='$$LDFLAGS ${OpenMP_CXX_FLAGS} ${OpenMP_EXE_LINKER_FLAGS}'")
+        endif()
+        separate_arguments(MEX_BUILD_FLAGS)
+
         ADD_CUSTOM_COMMAND(
             OUTPUT ${MEX_FILE}
             COMMAND ${MEX_REAL_CMD}
-            ARGS ${CMAKE_CURRENT_SOURCE_DIR}/${MEX_NAME}.cpp -I${PROJECT_SOURCE_DIR}/src/cpp -L${LIBRARY_OUTPUT_PATH} -lflann_s
+            ARGS ${CMAKE_CURRENT_SOURCE_DIR}/${MEX_NAME}.cpp -I${PROJECT_SOURCE_DIR}/src/cpp -L${LIBRARY_OUTPUT_PATH} -lflann_s ${MEX_BUILD_FLAGS}
             DEPENDS flann_s ${CMAKE_CURRENT_SOURCE_DIR}/${MEX_NAME}.cpp
             COMMENT "Building MEX extension ${MEX_FILE}"
         )