Commit: CI: disable -O2 for Coverity after v9.1.0429

[Christian Brabandt]

CI: disable -O2 for Coverity after v9.1.0429

Commit: https://github.com/vim/vim/commit/95ff39f8e3d5e16d4ef55f47d8f50da29df05f9e
Author: Christian Brabandt <c...@256bit.org>
Date: Wed May 22 07:53:23 2024 +0200

CI: disable -O2 for Coverity after v9.1.0429

gcc -O2 outputs this warning and turns it into an error when running
Coverity action:

```
eval.c: In function ‘echo_string_core’:
cc1: warning: function may return address of local variable [-Wreturn-local-addr]
eval.c:6495:12: note: declared here
6495 | char_u buf[MAX_FUNC_NAME_LEN];
| ^~~
```

This seems to be a false positive, so disable -O2 for Coverity
specifically.

Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/.github/workflows/coverity.yml b/.github/workflows/coverity.yml
index 290f7e4e4..90a6e9ff0 100644
--- a/.github/workflows/coverity.yml
+++ b/.github/workflows/coverity.yml
@@ -63,6 +63,9 @@ jobs:
# Append various warning flags to CFLAGS.
sed -i -f ci/config.mk.sed src/auto/config.mk
sed -i -f ci/config.mk.${CC}.sed src/auto/config.mk
+ # -O2 gives false warning and turns it into an error:
+ # warning: function may return address of local variable [-Wreturn-local-addr]
+ sed -i 's/-O2 \?//' src/auto/config.mk

- name: Build/scan vim
if: env.TOKEN