Index: head/Mk/Uses/alias.mk
===================================================================
--- head/Mk/Uses/alias.mk
+++ head/Mk/Uses/alias.mk
@@ -0,0 +1,31 @@
+# $FreeBSD$
+#
+# Add __FreeSBD__ definition to CFLAGS
+# Used by DPorts when masquerading as FreeBSD allows port to build without
+# additional patches
+#
+# Feature:      alias
+# Usage:        USES=alias or USES=alias:ARGS
+# Valid ARGS:   8, 9 (default), 10, 11
+#
+# MAINTAINER:	marino@FreeBSD.org
+
+.if !defined(_INCLUDE_USES_ALIAS_MK)
+_INCLUDE_USES_ALIAS_MK=    yes
+
+.if ${OPSYS} == DragonFly
+
+.if empty(alias_ARGS)
+CFLAGS+=	-D__FreeBSD__=9
+.else
+.  if ${alias_ARGS} == 8 || ${alias_ARGS} == 10 \
+   || ${alias_ARGS} == 9 || ${alias_ARGS} == 11
+CFLAGS+=	-D__FreeBSD__=${alias_ARGS}
+.  else
+IGNORE=	invalid MAJOR RELEASE argument (${alias_ARGS}) for USES=alias
+.  endif
+.endif
+
+.endif # OPSYS == DragonFly
+
+.endif