loader: silence implicit-load zink error by the loader

Since commit 7d9ea77b45 ("glx: add automatic zink fallback loading between hw
and sw drivers"), zink could be tried as a fallback. It'd better silence
if the zink loading is implicit and on fail as what commit 4cc975c6e9 ("glx: silence
more implicit-load zink errors") has done. But there seems to be one
left bebind, which is spit when building swrast but no zink with -Dglx=dri.

v2: plumb the flag through from egl/glx to the loader (zmike)

Signed-off-by: Luc Ma <luc@sietium.com>
Reviewed-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28970>

src/loader/loader.c

@@ -877,13 +877,15 @@ loader_open_driver_lib(const char *driver_name,
 const struct __DRIextensionRec **
 loader_open_driver(const char *driver_name,
                    void **out_driver_handle,
-                   const char **search_path_vars)
+                   const char **search_path_vars,
+                   bool driver_name_is_inferred)
 {
    char *get_extensions_name;
    const struct __DRIextensionRec **extensions = NULL;
    const struct __DRIextensionRec **(*get_extensions)(void);
+
    void *driver = loader_open_driver_lib(driver_name, "_dri", search_path_vars,
-                                         DEFAULT_DRIVER_DIR, true);
+                                         DEFAULT_DRIVER_DIR, !driver_name_is_inferred);
 
    if (!driver)
       goto failed;