Bug 783546. B2G macosx64_gecko builds should use the same clang as regular firefox builds. r=ted.

b2g/config/mozconfigs/macosx64_gecko/nightly

@@ -1,3 +1,5 @@
+. $topsrcdir/build/macosx/common
+
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
 ac_add_options --enable-update-packaging
 ac_add_options --enable-codesighs
@@ -16,7 +18,6 @@ mk_add_options MOZ_MAKE_FLAGS="-j12"
 
 # Treat warnings as errors in directories with FAIL_ON_WARNINGS.
 ac_add_options --enable-warnings-as-errors
-ac_add_options --with-ccache
 
 # B2G Stuff
 ac_add_options --enable-application=b2g