Compile warnings under -DMEMORY_CONTEXT_CHECKING and no assertions

Hi all,

When using -DMEMORY_CONTEXT_CHECKING, (also enforced by
-DUSE_VALGRIND), I am getting a couple of compiler warnings when
building without assertions:
aset.c: In function ‘AllocSetCheck’:
aset.c:1686:25: warning: variable ‘total_allocated’ set but not used
[-Wunused-but-set-variable=]
1686 | Size total_allocated = 0;
| ^~~~~~~~~~~~~~~
bump.c: In function ‘BumpCheck’:
bump.c:772:25: warning: variable ‘total_allocated’ set but not used
[-Wunused-but-set-variable=]
772 | Size total_allocated = 0;
| ^~~~~~~~~~~~~~~
generation.c: In function ‘GenerationCheck’:
generation.c:1137:25: warning: variable ‘total_allocated’ set but not
used [-Wunused-but-set-variable=]
1137 | Size total_allocated = 0;
| ^~~~~~~~~~~~~~~
slab.c: In function ‘SlabCheck’:
slab.c:1041:33: warning: variable ‘nblocks’ set but not used
[-Wunused-but-set-variable=]
1041 | int nblocks = 0;
| ^~~~~~~

All these ought to be marked with a PG_USED_FOR_ASSERTS_ONLY. Not
sure why nobody has seen that yet? I am using a gcc 16.1.1, nothing
fancy AFAIK.

Regards,
--
Michael