functions: add lookup for ARB functions

Instead of adding duplicate entries for functions that were originally
added as ARB extensions, just try to remove the ARB suffix, if we find
it (e.g., when asked to lookup "glGenBuffersARB" we will look for
"glGenBuffers").

src/functions.c

@@ -411,6 +411,17 @@ static int compare_proc(const void *a_ptr, const void *b_ptr)
 
 void *ogx_get_proc_address(const char *proc)
 {
+    char buffer[64];
+    size_t len;
+
+    /* If the string ends with the "ARB" suffix, remove it */
+    len = strlen(proc);
+    if (len > 3 && strcmp(proc + len - 3, "ARB") == 0) {
+        strncpy(buffer, proc, len - 3);
+        buffer[len - 3] = '\0';
+        proc = buffer;
+    }
+
     ProcMap search = { proc, NULL };
     ProcMap *elem = bsearch(&search, s_proc_map, NUM_PROCS, sizeof(ProcMap),
                             compare_proc);