diff --git a/Makefile b/Makefile
index 63b74e4..eef0808 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,7 @@ SILENT=@
 CFLAGS += -std=gnu99 -fPIC -fexceptions
 CXXFLAGS += -fPIC -fexceptions
 CPPFLAGS += -DTYPE_DEPENDENT_DISPATCH -DGNUSTEP
-CPPFLAGS += -D__OBJC_RUNTIME_INTERNAL__=1 -D_XOPEN_SOURCE=500 -D__BSD_VISIBLE=1
+CPPFLAGS += -D__OBJC_RUNTIME_INTERNAL__=1 -D_XOPEN_SOURCE=500 -D__BSD_VISIBLE=1 -D_BSD_SOURCE=1
 
 # Suppress warnings about incorrect selectors
 CPPFLAGS += -DNO_SELECTOR_MISMATCH_WARNINGS