Hey,

I tested a new version of the GNU screen on OpenBSD and found the bug.
I can't reproduce it on Linux, but it breaks a 'GNU screen' on OpenBSD
(crashes immediately after initialization. Just start 'screen')

The problem is here[1]. It seems that it's just the pointer problem (but I
don't understand why it works on Linux without any problem).
After it returns from the GrowBitfield function, the pointer to 'userbist'
is broken (address out of bounce [2]).

I compiled 'screen' on Linux with gcc and clang. It works.
I compiled it on OpenBSD with clang and gcc (CC=egcc). It crashed in both
cases.

I tried to play with sysctl vm.malloc_conf options [2], but it also doesn't
help.

Maybe someone will find time to analyze it and help me to understand/fix
this bug.
Thank you.

Cheers,
Alex

[1] https://git.savannah.gnu.org/cgit/screen.git/tree/src/acls.c#n103
[2] https://paste.opensuse.org/pastes/4934561ea6fb
[3] sysctl vm.malloc_conf='CFGJS<<'