Change `val` to `unsigned char` before being tested.
The fix is identical to the one that's been made in upstream jemalloc.
warning is:
src/malloc_io.c: In function ‘malloc_vsnprintf’:
src/malloc_io.c:369:2: warning: case label value exceeds maximum value for type
369 | case '?' | 0x80: \
| ^~~~
src/malloc_io.c:581:5: note: in expansion of macro ‘GET_ARG_NUMERIC’
581 | GET_ARG_NUMERIC(val, 'p');
| ^~~~~~~~~~~~~~~
9216b96b41