Remove some uses of mesonlib.run_once

These are basically doing what mlog.log(..., once=True) does, so lets
just use that. The once argument to mlog is newer, so these probably
should have been changed already.

mesonbuild/modules/gnome.py

@@ -83,11 +83,11 @@ class GnomeModule(ExtensionModule):
                          mlog.bold('https://bugzilla.gnome.org/show_bug.cgi?id=774368'))
 
     @staticmethod
-    @mesonlib.run_once
     def _print_gdbus_warning():
         mlog.warning('Code generated with gdbus_codegen() requires the root directory be added to\n'
                      '  include_directories of targets with GLib < 2.51.3:',
-                     mlog.bold('https://github.com/mesonbuild/meson/issues/1387'))
+                     mlog.bold('https://github.com/mesonbuild/meson/issues/1387'),
+                     once=True)
 
     @FeatureNewKwargs('gnome.compile_resources', '0.37.0', ['gresource_bundle', 'export', 'install_header'])
     @permittedKwargs({'source_dir', 'c_name', 'dependencies', 'export', 'gresource_bundle', 'install_header',

mesonbuild/modules/i18n.py

@@ -16,7 +16,7 @@ import shutil
 
 from os import path
 from .. import coredata, mesonlib, build, mlog
-from ..mesonlib import MesonException, run_once
+from ..mesonlib import MesonException
 from . import ModuleReturnValue
 from . import ExtensionModule
 from ..interpreterbase import permittedKwargs, FeatureNew, FeatureNewKwargs
@@ -59,9 +59,8 @@ PRESET_ARGS = {
 class I18nModule(ExtensionModule):
 
     @staticmethod
-    @run_once
     def nogettext_warning():
-        mlog.warning('Gettext not found, all translation targets will be ignored.')
+        mlog.warning('Gettext not found, all translation targets will be ignored.', once=True)
         return ModuleReturnValue(None, [])
 
     @staticmethod