util/u_debug: Use 'initialized' instead of 'first'

Using 'initialized' to guard the one-time init, means it can be set to
false as part of .bss instead setting 'first' to true in .data.  This
is more efficient and works at .ctor time.

Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16952>

src/util/u_debug.c

@@ -121,16 +121,16 @@ debug_print_blob(const char *name, const void *blob, unsigned size)
 static bool
 debug_get_option_should_print(void)
 {
-   static bool first = true;
+   static bool initialized = false;
    static bool value = false;
 
-   if (!first)
+   if (initialized)
       return value;
 
    /* Oh hey this will call into this function,
     * but its cool since we set first to false
     */
-   first = false;
+   initialized = true;
    value = debug_get_bool_option("GALLIUM_PRINT_OPTIONS", false);
    /* XXX should we print this option? Currently it wont */
    return value;