Reorder extra clang host flags

In make these clang-specific flags are marked as EXTRA and added after
the common flags.

This was causing differences between compiled objects in make and soong
because -fstack-protector-strong was before -fstack-protector in soong
instead of after.

Change-Id: I59dd6dcfdaf5ec9184a09e79efe80b62cfe48dbb
diff --git a/cc/x86_darwin_host.go b/cc/x86_darwin_host.go
index 1bd3dd0..7f4c489 100644
--- a/cc/x86_darwin_host.go
+++ b/cc/x86_darwin_host.go
@@ -63,10 +63,10 @@
 		"-Wl,-rpath,@loader_path/lib64",
 	}
 
-	darwinClangCflags = append([]string{
+	darwinClangCflags = append(clangFilterUnknownCflags(darwinCflags), []string{
 		"-integrated-as",
 		"-fstack-protector-strong",
-	}, clangFilterUnknownCflags(darwinCflags)...)
+	}...)
 
 	darwinClangLdflags = clangFilterUnknownCflags(darwinLdflags)