Thanks to Joshua in Macport team to provide a pointer regarding the very "Availability.h" issue is causedby duplicated inclusion of "Availability.h" in . directory. I commented out "-I." in Makefile.rules file to fix the compilation issue.Look likes we have solution for reported issue in R1. Not sure the impact of the omission of "-I." will do to other OS. How ?tj-yangs-imac:4.2.3 tj_yang$ diff -u build/Makefile.rules.orig build/Makefile.rules--- build/Makefile.rules.orig 2010-02-14 21:35:37.000000000 -0600+++ build/Makefile.rules 2010-02-14 21:36:24.000000000 -0600@@ -8,7 +8,7 @@ # Build targets ##################### -CFLAGS += -I. -I$(BUILDTOPDIR)/include+CFLAGS += -I$(BUILDTOPDIR)/include ifeq ($(CLIENTONLY),yes) BUILDTARGETS = clienttj-yangs-imac:4.2.3 tj_yang$ Why ?Don't know exactly why the change of gcc version to 4.2.1 in S.L. break the Makefile.rules files. R1: http://www.hswn.dk/hobbiton/2009/11/msg00311.html Cheers T.J. Yang _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469227/direct/01/