clang/gcc: Add build option FREECAD_WARN_ERROR to force to make warnings into errors

src/Mod/Surface/App/CMakeLists.txt

@@ -71,6 +71,9 @@ endif(FREECAD_USE_PCH)
 link_directories(${OCC_LIBRARY_DIR})
 add_library(Surface SHARED ${Surface_SRCS})
 target_link_libraries(Surface ${Surface_LIBS})
+if (FREECAD_WARN_ERROR)
+    target_compile_warn_error(Surface)
+endif()
 
 SET_BIN_DIR(Surface Surface /Mod/Surface)
 SET_PYTHON_PREFIX_SUFFIX(Surface)