diff --git a/config.project b/config.project
index 2dd5b37..d97f0cd 100644
--- a/config.project
+++ b/config.project
@@ -16,7 +16,7 @@ mb_default_shell=sh
 
 
 # switches
-mb_default_cflags_common="-std=c99 -D_XOPEN_SOURCE=700 -D_GNU_SOURCE"
+mb_default_cflags_common="-std=c99 -D_XOPEN_SOURCE=700 -D_BSD_SOURCE"
 mb_default_cflags_common="$mb_default_cflags_common -I\$(PROJECT_DIR)/src/internal"
 mb_default_cflags_common="$mb_default_cflags_common -I\$(PROJECT_DIR)/include"
 mb_default_cflags_common="$mb_default_cflags_common -Ibuild"