- `stdbool.h` is also included via system headers. Disabling it from curl
does not fix it. Silencing lots of these:
```
curl/lib/curlx/warnless.h:64:1: warning: '_Bool' is a C99 extension [-Wc99-extensions]
64 | bool curlx_sztouz(ssize_t sznum, size_t *puznum);
| ^
/Library/Developer/CommandLineTools/usr/lib/clang/17/include/stdbool.h:24:14: note: expanded from macro 'bool'
24 | #define bool _Bool
| ^
```
- silence `-Wcomma` warnings.
in favor of the global silencing approach, since a couple of more of
these were hit (in vquic, tool1622, unit1309, unit1636), and it seems
silly to update them all.
Revert e8189c4420#20362
Also:
- cmake: include C standard in 'platform flags' log line.
- GHA/macos: switch a job to C89 to verify.
- GHA/linux: show 'C89' in job names.
Ref: https://cmake.org/cmake/help/v3.7/variable/CMAKE_C_STANDARD.htmlCloses#20363
09c9afdd71