config: make scope_name non-static and rename it

To prepare for the upcoming --show-scope option, we require the ability
to convert a config_scope enum to a string.  As this was originally
implemented as a static function 'scope_name()' in
t/helper/test-config.c, we expose it via config.h and give it a less
ambiguous name 'config_scope_name()'

Signed-off-by: Matthew Rogers <mattr94@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config.c

@@ -3297,6 +3297,22 @@ const char *current_config_origin_type(void)
 	}
 }
 
+const char *config_scope_name(enum config_scope scope)
+{
+	switch (scope) {
+	case CONFIG_SCOPE_SYSTEM:
+		return "system";
+	case CONFIG_SCOPE_GLOBAL:
+		return "global";
+	case CONFIG_SCOPE_REPO:
+		return "repo";
+	case CONFIG_SCOPE_CMDLINE:
+		return "cmdline";
+	default:
+		return "unknown";
+	}
+}
+
 const char *current_config_name(void)
 {
 	const char *name;

config.h

@@ -301,6 +301,7 @@ enum config_scope {
 	CONFIG_SCOPE_REPO,
 	CONFIG_SCOPE_CMDLINE,
 };
+const char *config_scope_name(enum config_scope scope);
 
 enum config_scope current_config_scope(void);
 const char *current_config_origin_type(void);

t/helper/test-config.c

@@ -37,21 +37,6 @@
  *
  */
 
-static const char *scope_name(enum config_scope scope)
-{
-	switch (scope) {
-	case CONFIG_SCOPE_SYSTEM:
-		return "system";
-	case CONFIG_SCOPE_GLOBAL:
-		return "global";
-	case CONFIG_SCOPE_REPO:
-		return "repo";
-	case CONFIG_SCOPE_CMDLINE:
-		return "cmdline";
-	default:
-		return "unknown";
-	}
-}
 static int iterate_cb(const char *var, const char *value, void *data)
 {
 	static int nr;
@@ -63,7 +48,7 @@ static int iterate_cb(const char *var, const char *value, void *data)
 	printf("value=%s\n", value ? value : "(null)");
 	printf("origin=%s\n", current_config_origin_type());
 	printf("name=%s\n", current_config_name());
-	printf("scope=%s\n", scope_name(current_config_scope()));
+	printf("scope=%s\n", config_scope_name(current_config_scope()));
 
 	return 0;
 }