[Bug c++/121133] New: [13/14/15/16 Regression] __extension__ no longer silences the pedwarn for long long

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121133

            Bug ID: 121133
           Summary: [13/14/15/16 Regression] __extension__ no longer
                    silences the pedwarn for long long
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
__extension__ typedef long long tt;

```

With `-std=c++98 -pedantic` starting in GCC 4.5.0, a warning shows up:
```
<source>:1:15: warning: ISO C++ 1998 does not support 'long long'

```

But with the C front-end with `-std=c90 -pednatic` no warning shows up as
expected.