Change path_get_basename()'s return type to const char*

This makes it clear that the return value is immutable and moreover suggests
that the return vale is not allocated and thus should be treated carefully.

src/common.c

@@ -696,10 +696,10 @@ int _plist_dict_copy_item(plist_t target_dict, plist_t source_dict, const char *
 	return 0;
 }
 
-char* path_get_basename(char* path)
+const char* path_get_basename(char* path)
 {
 #ifdef WIN32
-	char *p = path + strlen(path);
+	const char *p = path + strlen(path);
 	while (p > path) {
 		if ((*p == '/') || (*p == '\\')) {
 			return p+1;
@@ -708,7 +708,7 @@ char* path_get_basename(char* path)
 	}
 	return p;
 #else
-	char *p = strrchr(path, '/');
+	const char *p = strrchr(path, '/');
 	return p ? p + 1 : path;
 #endif
 }

src/common.h

@@ -197,7 +197,7 @@ int _plist_dict_copy_data(plist_t target_dict, plist_t source_dict, const char *
 int _plist_dict_copy_string(plist_t target_dict, plist_t source_dict, const char *key, const char *alt_source_key);
 int _plist_dict_copy_item(plist_t target_dict, plist_t source_dict, const char *key, const char *alt_source_key);
 
-char* path_get_basename(char* path);
+const char* path_get_basename(char* path);
 
 #ifdef __cplusplus
 }

src/idevicerestore.c

@@ -987,8 +987,7 @@ int idevicerestore_start(struct idevicerestore_client_t* client)
 			if (stat(client->cache_dir, &st) < 0) {
 				mkdir_with_parents(client->cache_dir, 0755);
 			}
-			char* ipsw_basename = path_get_basename(client->ipsw->path);
-			ipsw_basename = strdup(ipsw_basename);
+			char* ipsw_basename = strdup(path_get_basename(client->ipsw->path));
 			char* p = strrchr(ipsw_basename, '.');
 			if (p && isalpha(*(p+1))) {
 				*p = '\0';