add gcc.musl build

I was thinking that the printf() differences
must be because Emscripten uses musl, but building
with musl natively seems fine.

Change-Id: Icf52d726a025239e4e8b255633e07dedfdc33baf
Reviewed-on: https://skia-review.googlesource.com/c/skcms/+/199821
Auto-Submit: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed