Create path_get_extension_mutable and use it in menu_explore function

for trivial extension replacement in string

libretro-common/file/file_path.c

@@ -214,6 +214,26 @@ const char *path_get_extension(const char *path)
    return "";
 }
 
+/**
+ * path_get_extension_mutable:
+ * @path               : path
+ *
+ * Specialized version of path_get_extension(). Return
+ * value is mutable.
+ *
+ * Gets extension of file. Only '.'s
+ * after the last slash are considered.
+ *
+ * @return extension part from the path.
+ **/
+char *path_get_extension_mutable(const char *path)
+{
+   char *ext = NULL;
+   if (!string_is_empty(path) && ((ext = strrchr(path_basename(path), '.'))))
+      return ext;
+   return NULL;
+}
+
 /**
  * path_remove_extension:
  * @path               : path

libretro-common/include/file/file_path.h

@@ -126,6 +126,20 @@ const char *path_get_archive_delim(const char *path);
  **/
 const char *path_get_extension(const char *path);
 
+/**
+ * path_get_extension_mutable:
+ * @path               : path
+ *
+ * Specialized version of path_get_extension(). Return
+ * value is mutable.
+ *
+ * Gets extension of file. Only '.'s
+ * after the last slash are considered.
+ *
+ * @return extension part from the path.
+ **/
+char *path_get_extension_mutable(const char *path);
+
 /**
  * path_remove_extension:
  * @path               : path

menu/menu_explore.c

@@ -522,8 +522,9 @@ explore_state_t *menu_explore_build_list(const char *directory_playlist,
          rdb_num = RHMAP_GET(rdb_indices, rdb_hash);
          if (!rdb_num)
          {
-            struct explore_rdb newrdb;
             size_t systemname_len;
+            struct explore_rdb newrdb;
+            char *ext_path        = NULL;
 
             newrdb.handle         = libretrodb_new();
             newrdb.count          = 0;
@@ -538,8 +539,18 @@ explore_state_t *menu_explore_build_list(const char *directory_playlist,
 
             fill_pathname_join_special(
                   tmp, directory_database, db_name, sizeof(tmp));
-            path_remove_extension(tmp);
+
-            strlcat(tmp, ".rdb", sizeof(tmp));
+            /* Replace the extension - change 'lpl' to 'rdb' */
+            if ((    ext_path = path_get_extension_mutable(tmp)) 
+                  && ext_path[0] == '.'
+                  && ext_path[1] == 'l'
+                  && ext_path[2] == 'p'
+                  && ext_path[3] == 'l')
+            {
+               ext_path[1] = 'r';
+               ext_path[2] = 'd';
+               ext_path[3] = 'b';
+            }
 
             if (libretrodb_open(tmp, newrdb.handle) != 0)
             {