uboot-ar71xx: fix compile on mac os x (patch from #9124)

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@26676 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/uboot-ar71xx/patches/021-darwin_compat.patch

@@ -0,0 +1,23 @@
+--- a/config.mk
++++ b/config.mk
+@@ -64,9 +64,17 @@ HOSTSTRIP	= strip
+ #
+ 
+ ifeq ($(HOSTOS),darwin)
+-HOSTCC		= cc
+-HOSTCFLAGS	+= -traditional-cpp
+-HOSTLDFLAGS	+= -multiply_defined suppress
++#get the major and minor product version (e.g. '10' and '6' for Snow Leopard)
++DARWIN_MAJOR_VERSION   = $(shell sw_vers -productVersion | cut -f 1 -d '.')
++DARWIN_MINOR_VERSION   = $(shell sw_vers -productVersion | cut -f 2 -d '.')
++
++before-snow-leopard    = $(shell if [ $(DARWIN_MAJOR_VERSION) -le 10 -a \
++   $(DARWIN_MINOR_VERSION) -le 5 ] ; then echo "$(1)"; else echo "$(2)"; fi ;)
++
++# Snow Leopards build environment has no longer restrictions as described above
++HOSTCC  = $(call before-snow-leopard, "cc", "gcc")
++HOSTCFLAGS += $(call before-snow-leopard, "-traditional-cpp")
++HOSTLDFLAGS    += $(call before-snow-leopard, "-multiply_defined suppress")
+ else
+ HOSTCC		= gcc
+ endif