[gtk/wip/baedert/for-master: 1/2] build: Make GCC ignore fallthrough comments

[Timm Bäder <baedert src gnome org>]

commit 7194196100bf7c08ba2d1d1664738efd6cd3fa78
Author: Timm Bäder <mail baedert org>
Date:   Thu Jan 27 16:05:33 2022 +0100

    build: Make GCC ignore fallthrough comments
    
    From the GCC manpage:
    
    > Wimplicit-fallthrough=5 doesn't recognize any comments as
    > fallthrough comments, only attributes disable
    > the warning.
    
    So, check for the =5 version after checking for the simple version. This
    way we get -Wfallhrough with clang and -Wfallthrough -Wfallthrough=5
    with GCC, which works.

 meson.build | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 65bf0b20af..4fbbb2f539 100644
--- a/meson.build
+++ b/meson.build
@@ -298,7 +298,8 @@ elif cc.get_id() == 'gcc' or cc.get_id() == 'clang'
     'array-bounds',
     'empty-body',
     'implicit',
-    'implicit-fallthrough',
+    'implicit-fallthrough',   # For non-gcc
+    'implicit-fallthrough=5', # For GCC, only recognize the attribute and no comments
     'init-self',
     'int-to-pointer-cast',
     'main',