submodule: refrain from filtering GIT_CONFIG_COUNT

14111fc ("git: submodule honor -c credential.* from command line",
2016-03-01) taught Git to pass through the GIT_CONFIG_PARAMETERS
environment variable when invoking a subprocess on behalf of a
submodule. But when d8d7715 ("config: allow specifying config entries
via envvar pairs", 2021-01-15) introduced support for GIT_CONFIG_COUNT
(and its associated GIT_CONFIG_KEY_? and GIT_CONFIG_VALUE_?), the
subprocess mechanism wasn't updated to also pass through these
variables.

Since they are conceptually the same (d8d7715 was written to address
a shortcoming of GIT_CONFIG_PARAMETERS), update the submodule subprocess
mechanism to also pass through GIT_CONFIG_COUNT.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: jonathantanmy

submodule.c

@@ -489,7 +489,8 @@ static void prepare_submodule_repo_env_no_git_dir(struct strvec *out)
 	const char * const *var;
 
 	for (var = local_repo_env; *var; var++) {
-		if (strcmp(*var, CONFIG_DATA_ENVIRONMENT))
+		if (strcmp(*var, CONFIG_DATA_ENVIRONMENT) &&
+		    strcmp(*var, CONFIG_COUNT_ENVIRONMENT))
 			strvec_push(out, *var);
 	}
 }