environment: rename 'namespace' variables

Rename C++ keyword in order to bring the codebase closer to being able
to be compiled with a C++ compiler.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

environment.c

@@ -98,7 +98,7 @@ int ignore_untracked_cache_config;
 /* This is set by setup_git_dir_gently() and/or git_default_config() */
 char *git_work_tree_cfg;
 
-static char *namespace;
+static char *git_namespace;
 
 static const char *super_prefix;
 
@@ -156,8 +156,8 @@ void setup_git_env(void)
 	free(git_replace_ref_base);
 	git_replace_ref_base = xstrdup(replace_ref_base ? replace_ref_base
 							  : "refs/replace/");
-	free(namespace);
-	namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));
+	free(git_namespace);
+	git_namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));
 	shallow_file = getenv(GIT_SHALLOW_FILE_ENVIRONMENT);
 	if (shallow_file)
 		set_alternate_shallow_file(shallow_file, 0);
@@ -191,9 +191,9 @@ const char *get_git_common_dir(void)
 
 const char *get_git_namespace(void)
 {
-	if (!namespace)
+	if (!git_namespace)
 		BUG("git environment hasn't been setup");
-	return namespace;
+	return git_namespace;
 }
 
 const char *strip_namespace(const char *namespaced_ref)