Fix a regression in 707d2f2fe8 (CI: use "$runs_on_pool", not
"$jobname" to select packages & config, 2021-11-23).
In that commit I changed CC=gcc from CC=gcc-9, but on OSX the "gcc" in
$PATH points to clang, we need to use gcc-9 instead. Likewise for the
linux-gcc job CC=gcc-8 was changed to the implicit CC=gcc, which would
select GCC 9.4.0 instead of GCC 8.4.0.
Furthermore in 25715419bf (CI: don't run "make test" twice in one
job, 2021-11-23) when the "linux-TEST-vars" job was split off from
"linux-gcc" the "cc_package: gcc-8" line was copied along with
it, so its "cc_package" line wasn't working as intended either.
As a table, this is what's changed by this commit, i.e. it only
affects the linux-gcc, linux-TEST-vars and osx-gcc jobs:
|-------------------+-----------+-------------------+-------+-------|
| jobname | vector.cc | vector.cc_package | old | new |
|-------------------+-----------+-------------------+-------+-------|
| linux-clang | clang | - | clang | clang |
| linux-sha256 | clang | - | clang | clang |
| linux-gcc | gcc | gcc-8 | gcc | gcc-8 |
| osx-clang | clang | - | clang | clang |
| osx-gcc | gcc | gcc-9 | clang | gcc-9 |
| linux-gcc-default | gcc | - | gcc | gcc |
| linux-TEST-vars | gcc | gcc-8 | gcc | gcc-8 |
|-------------------+-----------+-------------------+-------+-------|
Reported-by: Carlo Arenas <carenas@gmail.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>