Updated and fixed bugs along the way to support building for 1.2.10.

Note

The main fix also disable webp option via `skia_use_libwebp=false`.
Disabling of such option will solve the problem of linking error as
shown out as following

Undefined symbols for architecture x86_64:
  "is_orientation_marker(unsigned char const*, unsigned long, SkEncodedOrigin*)", referenced from:
      SkWebpCodec::MakeFromStream(std::__1::unique_ptr<SkStream, std::__1::default_delete<SkStream> >, SkCodec::Result*) in libskia.a(webp.SkWebpCodec.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

so to aim to support both worlds of users, this release disabled such
option.

Build script for Aseprite 1.2.9

Build script for Aseprite 1.2.6