Fix: [CMake] Check nforenum and grfcodec return value

cmake/scripts/CreateGRF.cmake

@@ -39,6 +39,20 @@ foreach(NFO_LINE IN LISTS NFO_LINES)
     endif()
 endforeach()
 
-execute_process(COMMAND ${NFORENUM_EXECUTABLE} -s sprites/${GRF_SOURCE_FOLDER_NAME}.nfo)
-execute_process(COMMAND ${GRFCODEC_EXECUTABLE} -n -s -e -p1 ${GRF_SOURCE_FOLDER_NAME}.grf)
+execute_process(COMMAND ${NFORENUM_EXECUTABLE} -s sprites/${GRF_SOURCE_FOLDER_NAME}.nfo RESULT_VARIABLE RESULT)
+if(RESULT)
+    if(NOT RESULT MATCHES "^[0-9]*$")
+        message(FATAL_ERROR "Failed to run NFORenum (${RESULT}), please check NFORENUM_EXECUTABLE variable")
+    endif()
+    message(FATAL_ERROR "NFORenum failed")
+endif()
+
+execute_process(COMMAND ${GRFCODEC_EXECUTABLE} -n -s -e -p1 ${GRF_SOURCE_FOLDER_NAME}.grf RESULT_VARIABLE RESULT)
+if(RESULT)
+    if(NOT RESULT MATCHES "^[0-9]*$")
+        message(FATAL_ERROR "Failed to run GRFCodec (${RESULT}), please check GRFCODEC_EXECUTABLE variable")
+    endif()
+    message(FATAL_ERROR "GRFCodec failed")
+endif()
+
 execute_process(COMMAND ${CMAKE_COMMAND} -E copy ${GRF_SOURCE_FOLDER_NAME}.grf ${GRF_BINARY_FILE})