Google3 apps are still using Create* shader methods.

This may need to go in DEFINES_ALL,
but definitely needs to affect the main _UNIX builds.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1808723002

Review URL: https://codereview.chromium.org/1808723002

public.bzl

@@ -498,6 +498,7 @@ DEFINES_UNIX = [
     "SK_CODEC_DECODES_PNG",
     "SK_CODEC_DECODES_RAW",
     "SK_CODEC_DECODES_WEBP",
+    "SK_SUPPORT_LEGACY_CREATESHADER_PTR",
 ]
 
 DEFINES_ANDROID = [