Update mac_sdk_versions_supported.

Now we requires Mac OS X SDK version at least 10.8.
Also removed the unnecessary sort call in getting
mac_sdk_versions_installed.
Lexical sort doesn't make sense when 10.10 is added to that list.
Actually the next makefile line makes sure we always get the first
match in $(mac_sdk_versions_supported):
mac_sdk_version := $(firstword $(filter $(mac_sdk_versions_installed),
$(mac_sdk_versions_supported)))

Bug: 22825165
Change-Id: I4bfafabb11f94b66704d4799fe61fe3f16429538
diff --git a/core/combo/mac_version.mk b/core/combo/mac_version.mk
index 6defba7..638e3a0 100644
--- a/core/combo/mac_version.mk
+++ b/core/combo/mac_version.mk
@@ -9,7 +9,7 @@
 
 build_mac_version := $(shell sw_vers -productVersion)
 
-mac_sdk_versions_supported :=  10.6 10.7 10.8 10.9
+mac_sdk_versions_supported :=  10.8 10.9 10.10
 ifneq ($(strip $(MAC_SDK_VERSION)),)
 mac_sdk_version := $(MAC_SDK_VERSION)
 ifeq ($(filter $(mac_sdk_version),$(mac_sdk_versions_supported)),)
@@ -19,7 +19,7 @@
 $(error Stop.)
 endif
 else
-mac_sdk_versions_installed := $(shell xcodebuild -showsdks | grep macosx | sort | sed -e "s/.*macosx//g")
+mac_sdk_versions_installed := $(shell xcodebuild -showsdks | grep macosx | sed -e "s/.*macosx//g")
 mac_sdk_version := $(firstword $(filter $(mac_sdk_versions_installed), $(mac_sdk_versions_supported)))
 ifeq ($(mac_sdk_version),)
 mac_sdk_version := $(firstword $(mac_sdk_versions_supported))