diff --git a/src/Makefile.am b/src/Makefile.am
index 153c7b8..0bfeb07 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -6,6 +6,7 @@ CFLAGS = -Wall -Wextra -Wno-unused-variable -Wno-unused-parameter
 AM_CPPFLAGS = \
 	-I$(top_builddir) \
 	-isystem $(top_srcdir)/include/bsd/ \
+	-include $(top_builddir)/config.h \
 	-DLIBBSD_OVERLAY -DLIBBSD_DISABLE_DEPRECATED \
 	-D_GNU_SOURCE -D__REENTRANT