A user reported issues building GnuPG failing at ../../g10/gpg2 --homedir .
--quiet --yes --no-permission-warning --import ./pubdemo.asc

gpg: signal Segmentation fault caught ... exiting

Upon looking into the issue it was determined that it is specific to the x32 ABI
and can be corrected by specifying BYTES_PER_MPI_LIMB correctly for this ABI in
libgcrypt.

A proposed patch has been sent to the gcrypt-devel mailing list with title
[PATCH] Fix a segfault for x32 ABIs resulting in erronuous detection, of size
for BYTES_PER_MPI_LIMB

Additional information at https://bugs.gentoo.org/show_bug.cgi?id=512762