port-vax/58290: VAX port does not support _UC_TLSBASE

[thorpej%me.com@localhost]

>Number:         58290
>Category:       port-vax
>Synopsis:       VAX port does not support _UC_TLSBASE
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-vax-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon May 27 22:00:01 +0000 2024
>Originator:     Jason Thorpe
>Release:        10.0_RC1
>Organization:
Society for the Preservation of VMS Alternatives
>Environment:
NetBSD vax-vm 10.0_RC1 NetBSD 10.0_RC1 (GENERIC) #0: Wed Nov 29 12:36:24 UTC 2023  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/vax/compile/GENERIC vax

>Description:
NetBSD/vax does not support _UC_TLSBASE, largely because there is no room left in ucontext_t.
>How-To-Repeat:
Visible in automated test results:

t_swapcontext (2/3): 2 test cases
    swapcontext1: [0.090000s] Failed: /usr/src/tests/lib/libc/sys/t_swapcontext.c:87: nctx.uc_flags & _UC_TLSBASE not met
    swapcontext2: [0.090001s] Failed: /usr/src/tests/lib/libc/sys/t_swapcontext.c:87: nctx.uc_flags & _UC_TLSBASE not met
[0.210001s]

>Fix:
Not provided here.