pmemcheck: build issue on some OSes

[janekmi]

Environment Information

• OS(es) version(s): RockyLinux 8; Ubuntu 22.04

https://github.com/pmem/pmdk/actions/runs/5720109172/job/15499410906#step:3:3002
https://github.com/pmem/pmdk/actions/runs/5720109172/job/15499411079#step:3:3349

Please provide a reproduction of the bug:

./pull-or-rebuild-image.sh rebuild

How often bug is revealed: (always, often, rare): always

Actual behavior:

In function 'read_cache_line_size',
    inlined from 'pmc_post_clo_init' at pmc_main.c:2081:29:
pmc_main.c:1413:37: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
 1413 |         read_buffer[proc_read_size] = 0;
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
pmc_main.c: In function 'pmc_post_clo_init':
pmc_main.c:1409:10: note: at offset 2048 into destination object 'read_buffer' of size 2048
 1409 |     char read_buffer[proc_read_size];
      |          ^~~~~~~~~~~

Expected behavior:

No warning.

Additional information about Priority and Help Requested:

Requested priority: Low

Note: It is not known what consequences this issue might cause.