solved by a simple 'make world'. The signalcontext function was going
to the trouble of generating an even 16 byte alignment, but in fact it
needed to be odd aligned to simulate the 8-byte return address having
been pushed by the caller. This fixes yet another group of crashes in
applications using libpthread. And yet again, it was my fault all along.
While here, rename the duplicate internal ctx_wrapper() functions to
makectx_wrapper() and sigctx_wrapper() so that traces aren't ambiguous.
ABI-required stack alignment. C code expects that the push of the
return address disturbed the 16 byte alignment and it will take corrective
measures to fix it before making another call. Of course, if its wrong
to start with, then all hell breaks loose. Essentially we "fix" this
by making the stack alignment odd to start with.
This was one of the things that broke on libkse with apps that use
floating point/varargs/etc.
Approved by: re (scottl)
