Reviewed warning

src/rlgl.h

@@ -2425,7 +2425,7 @@ void rlLoadExtensions(void *loader)
 
     // Get supported extensions list
     GLint numExt = 0;
-    const char **extList = (char **)RL_MALLOC(512*sizeof(const char *)); // Allocate 512 strings pointers (2 KB)
+    const char **extList = (const char **)RL_MALLOC(512*sizeof(const char *)); // Allocate 512 strings pointers (2 KB)
     const char *extensions = (const char *)glGetString(GL_EXTENSIONS);  // One big const string
 
     // NOTE: We have to duplicate string because glGetString() returns a const string