Fix formating problems with GetApplicationDir.

Don't ever return an empty string

src/rcore.c

@@ -3068,6 +3068,10 @@ const char *GetApplicationDirectory(void)
             }
         }
     }
+    else
+    {
+        appDir[0] = '/';
+    }
 #elif defined(__APPLE__)
     uint32_t size = sizeof(appDir);
 
@@ -3083,6 +3087,10 @@ const char *GetApplicationDirectory(void)
             }
         }
     }
+    else
+    {
+        appDir[0] = '/';
+    }
 #endif
 
     return appDir;