build/clang_darwin: Set CC before trying to run CheckArches.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@144661 91177308-0d34-0410-b5e6-96231b3b80d8

Author: ddunbar

make/platform/clang_darwin.mk

@@ -22,6 +22,8 @@ CheckArches = \
 
 ###
 
+CC := clang
+
 Configs :=
 UniversalArchs :=
 
@@ -67,8 +69,6 @@ endif
 
 ###
 
-CC := clang
-
 # Forcibly strip off any -arch, as that totally breaks our universal support.
 override CC := $(subst -arch ,-arch_,$(CC))
 override CC := $(patsubst -arch_%,,$(CC))