ci: exercise credential helpers

Wire up credential helpers in our CI runs so that we can rest assured
that they compile and (if tests are available) function correctly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

ci/lib.sh

@@ -348,6 +348,9 @@ case "$jobname" in
 linux32)
 	CC=gcc
 	;;
+linux-meson)
+	MESONFLAGS="$MESONFLAGS -Dcredential_helpers=libsecret,netrc"
+	;;
 linux-musl-meson)
 	MESONFLAGS="$MESONFLAGS -Dtest_utf8_locale=C.UTF-8"
 	;;
@@ -359,6 +362,9 @@ linux-asan-ubsan)
 	export NO_SVN_TESTS=LetsSaveSomeTime
 	MAKEFLAGS="$MAKEFLAGS NO_PYTHON=YepBecauseP4FlakesTooOften"
 	;;
+osx-meson)
+	MESONFLAGS="$MESONFLAGS -Dcredential_helpers=osxkeychain"
+	;;
 esac
 
 MAKEFLAGS="$MAKEFLAGS CC=${CC:-cc}"