[vte] build: Suppress undesirable warnings

[Christian Persch <chpe src gnome org>]

commit 1b60b4a600dbbec0a056f076f1aae244b1a1109c
Author: Christian Persch <chpe src gnome org>
Date:   Sat Mar 13 22:10:42 2021 +0100

    build: Suppress undesirable warnings

 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/meson.build b/meson.build
index 7d30ffab..393ecd83 100644
--- a/meson.build
+++ b/meson.build
@@ -388,6 +388,12 @@ compiler_flags_cxx_required = [
   '-fvisibility=hidden',
 ]
 
+if cxx.get_id() == 'clang'
+  compiler_flags_cxx_only += [
+    '-Wno-unknown-attributes', # get rid of warnings about unimplemented [[(un)likely]]
+  ]
+endif
+
 global_cflags = cc.get_supported_arguments(compiler_flags_common +
                                            compiler_flags_common_undesirable +
                                            compiler_flags_c_only)