--- libmalloc/libmalloc-67/xcodescripts/manpages.sh
+++ libmalloc/libmalloc-140.50.6/xcodescripts/manpages.sh
@@ -3,7 +3,8 @@
 if [ "$ACTION" = installhdrs ]; then exit 0; fi
 if [[ "$PLATFORM_NAME" != "macosx" ]]; then exit 0; fi
 
-UNIFDEF_FLAGS="-D__OPEN_SOURCE__"
+UNIFDEF_FLAGS=""
+
 MANPAGES_LIST="${SRCROOT}/man/manpages.lst"
 FILES=$(find -E ${SRCROOT} -regex '.*/[^.]+\.[0-9]' -type f)