diff --git a/build/autoconf/lustre-build-darwin.m4 b/build/autoconf/lustre-build-darwin.m4
index 8cbc7560be11d3ea058898bde666297a52de2fcf..fbe515ad64bafbf0d5a6493c3aa4d895525c653a 100644
--- a/build/autoconf/lustre-build-darwin.m4
+++ b/build/autoconf/lustre-build-darwin.m4
@@ -62,6 +62,17 @@ EXTRA_KCFLAGS="$EXTRA_KCFLAGS -msoft-float -static"
 EXTRA_KCFLAGS="$EXTRA_KCFLAGS -DKERNEL -DKERNEL_PRIVATE"
 EXTRA_KCFLAGS="$EXTRA_KCFLAGS -DDRIVER_PRIVATE -DAPPLE -DNeXT"
 EXTRA_KCFLAGS="$EXTRA_KCFLAGS -D__KERNEL__ -D__DARWIN__"
+#
+# C flags for Panther/Tiger
+#
+case $target_os in
+        darwin8*)
+                EXTRA_KCFLAGS="$EXTRA_KCFLAGS -D__DARWIN8__"
+        darwin7*)
+                EXTRA_KCFLAGS="$EXTRA_KCFLAGS -D__DARWIN7__"
+        ;;
+esac
+
 #
 # Debugging flags. Remove!
 #