[vte] build: Fix build on meson 0.49

[Christian Persch <chpe src gnome org>]

commit ba7d6416a4bbfe0b0ca4c53f222b5fabd5bdaa72
Author: Christian Persch <chpe src gnome org>
Date:   Mon Apr 29 11:09:16 2019 +0200

    build: Fix build on meson 0.49

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 44a417ab..3760b3f8 100644
--- a/meson.build
+++ b/meson.build
@@ -23,7 +23,7 @@ project(
     'buildtype=release',
     'c_std=gnu11',
     'cpp_std=gnu++17',
-    'warning_level=0',
+    'warning_level=' + (meson.version().version_compare('>= 0.50.0') ? '0' : '1'),
     'b_ndebug=false',
   ],
   meson_version: '>= 0.49.0',