[ARM] sysv-style ucontext functions appear not to be implemented on armel

[Dave Martin]

When called, getcontext() returns -1 and sets errno = ENOSYS.

Some packages, such as wvstreams (a wvdial backend package), currently rely on the ucontext functions in order to work correctly; currently such packages are broken on armel.

See also http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521473

[Paul Larson (pwlars)]

Combined this with bug #383978
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To work around this, wvstreams should be ported to use another mechanism such as setjmp/longjmp (I haven't investigated the feasibility of this), or the affected functions (primarily setcontext and getcontext) need to be implemented in glibc.

The affected code is in utils/wvtask.cc. I don't think the functions are used anywhere else.
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It seems that probably either ucontext should be implemented or a workaround described above for wvstreams, but it makes sense to track them both here since probably only one should be implemented and shouldn't be done blindly to the other.

[Paul Larson (pwlars)]

Setting these both to medium, but in reality, the wvstreams one should be closed if a decision is made to add support for getcontext on armel

[Jani Monoses (jani)]

a setjmp/longjmp based fallback mechanism is used in GNU Pth but that too is currently broken
https://bugs.launchpad.net/ubuntu/+source/pth/+bug/599862