diff --git a/config.project b/config.project
index 2c2452e..b93196c 100644
--- a/config.project
+++ b/config.project
@@ -33,6 +33,7 @@ mb_ccenv_skip_native=
 # switches
 mb_default_cflags_common="-std=c99 -D_BSD_SOURCE -D_XOPEN_SOURCE=700"
 mb_default_cflags_common="$mb_default_cflags_common -I\$(SOURCE_DIR)/src/internal"
+mb_default_cflags_common="$mb_default_cflags_common -I\$(SOURCE_DIR)/src"
 mb_default_cflags_common="$mb_default_cflags_common -I\$(SOURCE_DIR)/include"
 mb_default_cflags_common="$mb_default_cflags_common -Ibuild"