[gtk+] build: Bump minimum Meson version to 0.42.1

[Debarshi Ray <debarshir src gnome org>]

commit edaaefcb744f994cbe17e4b348898540b5c71da1
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Sep 18 18:04:34 2017 +0200

    build: Bump minimum Meson version to 0.42.1
    
    Otherwise it fails to build with:
    
      FAILED: gtk/im-ipa@sha/imipa.c.o
      ...
      In file included from ../gtk/gtkintl.h:4:0,
                       from ../modules/input/imipa.c:28:
      /opt/include/glib-2.0/glib/gi18n-lib.h:27:2: error: #error You must
              define GETTEXT_PACKAGE before including gi18n-lib.h. Did you
              forget to include config.h?
       #error You must define GETTEXT_PACKAGE before
               including gi18n-lib.h.  Did you forget to include config.h?
        ^~~~~
      ../modules/input/imipa.c:144:3: error: ‘GETTEXT_PACKAGE’ undeclared
              here (not in a function)
         GETTEXT_PACKAGE,     /* Translation domain */
         ^~~~~~~~~~~~~~~
      ../modules/input/imipa.c:145:4: error: ‘GTK_LOCALEDIR’ undeclared
              here (not in a function)
          GTK_LOCALEDIR,     /* Dir for bindtextdomain (not strictly
                  needed for "gtk+") */
          ^~~~~~~~~~~~~

 meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index 5056352..8135e52 100644
--- a/meson.build
+++ b/meson.build
@@ -7,7 +7,7 @@ project('gtk+-4.0', 'c',
           # https://github.com/mesonbuild/meson/issues/2289
           'c_std=gnu99',
         ],
-        meson_version : '>= 0.40.0',
+        meson_version : '>= 0.42.1',
         license: 'LGPLv2.1+')
 
 glib_major_req = 2