diff --git a/Makefile.am b/Makefile.am
index 2542175b7a..96fe24b8f0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1189,6 +1189,7 @@ GLIB_GENERATED += \
 	libnm-core/tests/nm-core-tests-enum-types.h \
 	libnm-core/tests/nm-core-tests-enum-types.c
 nm_core_tests_enum_types_sources = libnm-core/tests/test-general-enums.h
+nm_core_tests_enum_types_MKENUMS_C_FLAGS = --fhead '\#include "nm-default.h"\n'
 
 libnm-core/tests/nm-core-tests-enum-types.h.stamp: libnm-core/tests/.dirstamp
 libnm-core/tests/nm-core-tests-enum-types.c.stamp: libnm-core/tests/.dirstamp