fix: set osxcross CC for darwin cross-compile in goreleaser

Darwin builds were inheriting the goreleaser-cross container's default
linux gcc, which rejects clang's -arch flag. Point CC at o64-clang /
oa64-clang so CGO picks up the osxcross toolchain.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: radim

.goreleaser.yaml

@@ -14,6 +14,7 @@ builds:
     binary: qshape
     env:
       - CGO_ENABLED=1
+      - 'CC={{- if eq .Arch "arm64" -}}oa64-clang{{- else -}}o64-clang{{- end -}}'
     goos: [darwin]
     goarch: [amd64, arm64]
     ldflags: