SDL: Added an SDL error to SDL_GameControllerMapping* functions

From 24f97dd700a883437c1bdc375988cfc7163b262e Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Thu, 11 Aug 2022 14:39:49 -0700
Subject: [PATCH] Added an SDL error to SDL_GameControllerMapping* functions

---
 src/joystick/SDL_gamecontroller.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/joystick/SDL_gamecontroller.c b/src/joystick/SDL_gamecontroller.c
index 6b45340383c..4d79d9bf169 100644
--- a/src/joystick/SDL_gamecontroller.c
+++ b/src/joystick/SDL_gamecontroller.c
@@ -1614,6 +1614,8 @@ SDL_GameControllerMappingForIndex(int mapping_index)
             return CreateMappingString(mapping, mapping->guid);
         }
         --mapping_index;
+    } else {
+        SDL_SetError("Mapping not available");
     }
     return NULL;
 }
@@ -1627,6 +1629,8 @@ SDL_GameControllerMappingForGUID(SDL_JoystickGUID guid)
     ControllerMapping_t *mapping = SDL_PrivateGetControllerMappingForGUID(guid, SDL_FALSE);
     if (mapping) {
         return CreateMappingString(mapping, guid);
+    } else {
+        SDL_SetError("Mapping not available");
     }
     return NULL;
 }