ci/alpine: build Mesa on top of Alpine 3.16

Alpine is lightweight distribution with musl-libc. We currently testing
with Debian and Fedora, which are both Glibc based distro, so this
option should be able give us chance to catch more build-system bugs.

Acked-by: Yonggang Luo <luoyonggang@gmail.com>
Signed-off-by: David Heidelberg <david.heidelberg@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19588>

.gitlab-ci/container/container_pre_build.sh

@@ -2,6 +2,8 @@
 
 if test -f /etc/debian_version; then
     CCACHE_PATH=/usr/lib/ccache
+elif test -f /etc/alpine-release; then
+    CCACHE_PATH=/usr/lib/ccache/bin
 else
     CCACHE_PATH=/usr/lib64/ccache
 fi