[PATCH 2/3] ci: avoid bare "gcc" for osx-gcc job

On macOS, a bare "gcc" (without a version) will invoke a wrapper for clang, not actual gcc. Even when gcc is installed via homebrew, that only provides version-specific links in /usr/local/bin (like "gcc-13"), and never a version-agnostic "gcc" wrapper.

As far as I can tell, this has been the case for a long time, and this osx-gcc job has largely been doing nothing. We can point it at "gcc-13", which will pick up the homebrew-installed version.

The fix here is specific to the github workflow file, as the gitlab one does not have a matching job.

It's a little unfortunate that we cannot just ask for the latest version of gcc which homebrew provides, but as far as I can tell there is no easy alias (you'd have to find the highest number gcc-* in /usr/local/bin yourself).

Signed-off-by: Jeff King <peff@peff.net>
---
We'll eventually have to bump "gcc-13" to "gcc-14" here, and so on. I
don't think we ever cared about gcc-13 in particular; it's just that
older versions of the runner image had some ancient version which we
wanted to avoid.

 .github/workflows/main.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)