Commit Briefs
don't allocate BIGNUM on the stack
on fedora 33 the BIGNUM type is opaque. Allocate always to avoid headaches.
revert commit 346f28eeaa205d268d1e63c7ffd86cf041f6d1e6
keep mark_nonblock in utils.c, as otherwise the build for the regress suite will fail (mark_nonblock needs fatal which is in gmid.c, and we can't link gmid.o with the regress suite...)