Update android_make to support both --gcc and --clang options.

This CL also fixes all the errors that resulted from compiling
with clang and ccache.

BUG=skia:4948
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1774503004

Review URL: https://codereview.chromium.org/1774503004
diff --git a/tools/android/SkAndroidSDKCanvas.h b/tools/android/SkAndroidSDKCanvas.h
index d8ee0ed..68a5381 100644
--- a/tools/android/SkAndroidSDKCanvas.h
+++ b/tools/android/SkAndroidSDKCanvas.h
@@ -72,7 +72,7 @@
     void onDrawImage(const SkImage*, SkScalar, SkScalar, const SkPaint*) override;
     void onDrawImageRect(const SkImage*, const SkRect*, const SkRect&, const SkPaint*,
                          SrcRectConstraint) override;
-    void onDrawPicture(const SkPicture*, const SkMatrix*, const SkPaint*);
+    void onDrawPicture(const SkPicture*, const SkMatrix*, const SkPaint*) override;
     void onDrawAtlas(const SkImage*, const SkRSXform[], const SkRect[],
                      const SkColor[], int count, SkXfermode::Mode,
                      const SkRect* cull, const SkPaint*) override;