coroutine tests fail on OpenBSD with segmentation faults

[euantorano]

The coroutine tests tests/coroutines/tgc.nim and tests/coroutines/twait.nim both fail on OpenBSD with segmentaiton faults:

nim c -r tests/coroutines/tgc.nim
Hint: used config file '/home/euant/Nim/config/nim.cfg' [Conf]
Hint: used config file '/home/euant/Nim/config/config.nims' [Conf]
Hint: used config file '/home/euant/Nim/tests/config.nims' [Conf]
Hint: used config file '/home/euant/Nim/tests/coroutines/tgc.nim.cfg' [Conf]
Hint: 15794 LOC; 0.020 sec; 17.086MiB peakmem; Debug build; proj: tgc; out: tgc [SuccessX]
Hint: /home/euant/Nim/tests/coroutines/tgc  [Exec]
Segmentation fault (core dumped)
Error: execution of an external program failed: '/home/euant/Nim/tests/coroutines/tgc '

nim c -r tests/coroutines/twait
Hint: used config file '/home/euant/Nim/config/nim.cfg' [Conf]
Hint: used config file '/home/euant/Nim/config/config.nims' [Conf]
Hint: used config file '/home/euant/Nim/tests/config.nims' [Conf]
Hint: used config file '/home/euant/Nim/tests/coroutines/twait.nim.cfg' [Conf]
Hint: system [Processing]
Hint: widestrs [Processing]
Hint: io [Processing]
Hint: twait [Processing]
Hint: coro [Processing]
Hint: os [Processing]
Hint: strutils [Processing]
Hint: parseutils [Processing]
Hint: math [Processing]
Hint: bitops [Processing]
Hint: macros [Processing]
Hint: algorithm [Processing]
Hint: unicode [Processing]
Hint: pathnorm [Processing]
Hint: osseps [Processing]
Hint: posix [Processing]
Hint: times [Processing]
Hint: options [Processing]
Hint: typetraits [Processing]
Hint: lists [Processing]
Hint: clang -c  -w -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0   -I/home/euant/Nim/lib -I/home/euant/Nim/tests/coroutines -o /home/euant/.cache/nim/twait_d/amd64.S.o /home/euant/Nim/lib/arch/x86/amd64.S [Exec]
Hint:  [Link]
Hint: 53047 LOC; 1.220 sec; 75.594MiB peakmem; Debug build; proj: twait; out: twait [SuccessX]
Hint: /home/euant/Nim/tests/coroutines/twait  [Exec]
Segmentation fault (core dumped)
Error: execution of an external program failed: '/home/euant/Nim/tests/coroutines/twait '

Looking at /var/log/messages I can see the following logged:

Apr 20 15:00:17 openbsd-vm /bsd: [tgc]26913/58784 sp=5ce4ae8abc0 inside 7f7fffbf8000-7f7fffff7000: not MAP_STACK
Apr 20 15:00:17 openbsd-vm /bsd: [tgc]26913/58784 sp=5ce4ae8a710 inside 7f7fffbf8000-7f7fffff7000: not MAP_STACK
Apr 20 15:01:05 openbsd-vm /bsd: [twait]71793/411299 sp=cd7844bebc0 inside 7f7fffbce000-7f7ffffcd000: not MAP_STACK
Apr 20 15:01:05 openbsd-vm /bsd: [twait]71793/411299 sp=cd7844be710 inside 7f7fffbce000-7f7ffffcd000: not MAP_STACK

[euantorano]

Fixed in #14682.