[bazel] Fix Windows build of //example/external_client:use_ganesh_gl

Bug: b/256860862
Change-Id: Id74ef9e7baaf5614a30aaa732a035cf832a21d83
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/894419
Reviewed-by: Kaylee Lubick <kjlubick@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
9 files changed