Fix stripping on Darwin

The strip tool is different on Darwin, use a separate darwinStrip rule
instead of calling strip.sh for host builds on Darwin.

Change-Id: I6d421cba0dcea04367d5bc638a03f64c81e2ead0
diff --git a/cc/cc.go b/cc/cc.go
index 052df2b..1a8ba3b 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -1979,10 +1979,14 @@
 
 func (stripper *stripper) strip(ctx ModuleContext, in, out common.ModuleOutPath,
 	flags builderFlags) {
-	flags.stripKeepSymbols = stripper.StripProperties.Strip.Keep_symbols
-	// TODO(ccross): don't add gnu debuglink for user builds
-	flags.stripAddGnuDebuglink = true
-	TransformStrip(ctx, in, out, flags)
+	if ctx.Darwin() {
+		TransformDarwinStrip(ctx, in, out)
+	} else {
+		flags.stripKeepSymbols = stripper.StripProperties.Strip.Keep_symbols
+		// TODO(ccross): don't add gnu debuglink for user builds
+		flags.stripAddGnuDebuglink = true
+		TransformStrip(ctx, in, out, flags)
+	}
 }
 
 func testPerSrcMutator(mctx common.AndroidBottomUpMutatorContext) {