diff --git a/pytriqs/wrap_generator/wrapper_desc_generator.py.in b/pytriqs/wrap_generator/wrapper_desc_generator.py.in
index b49dbdea..afc3919a 100644
--- a/pytriqs/wrap_generator/wrapper_desc_generator.py.in
+++ b/pytriqs/wrap_generator/wrapper_desc_generator.py.in
@@ -41,7 +41,7 @@ if __name__ == '__main__' :
     compiler_options += ['-I%s'%x for x in args.includes]
     add_opts = '@TRIQS_LIBCLANG_CXX_ADDITIONAL_FLAGS@'.strip()
     if add_opts:
-        compiler_options.append(add_opts)
+        compiler_options += add_opts.split()
 
     functions, classes = parse(args.filename, debug = False, compiler_options = compiler_options, where_is_libclang = args.libclang_location)