Following change should be useful:
Index: bootstrap
===================================================================
RCS file: /cvsroot/pkgsrc/bootstrap/bootstrap,v
retrieving revision 1.200
diff -u -r1.200 bootstrap
--- bootstrap 3 Oct 2013 01:24:57 -0000 1.200
+++ bootstrap 18 Nov 2013 02:30:58 -0000
@@ -531,6 +531,7 @@
;;
esac
unset osrev macosx_version
+ check_compiler=yes
;;
DragonFly)
root_group=wheel
@@ -867,6 +868,9 @@
compiler="gcc"
else
case "$opsys" in
+ Darwin) compiler="clang"
+ test -n "$CC" || CC=clang
+ ;;
IRIX)
if [ `uname -r` -ge 6 ]; then
compiler="mipspro"