Make sure to build kernel files with -fno-pie; this had been forgotten while
switching the m88k toolchain to PIE by default, and I am quite impressed
kernels built with PIE objects run without problems.
Remove replaying of the 88100 data pipeline in sigreturn().
This had been added during the r1.18->r1.22 changes to let the testcases from
the devel/libsigsegv run.
Contrary to what I wrote then, the pipeline gets replayed when returning to
userland to invoke the signal handler, so there is no need to do this once more
in sigreturn.
The real fix needed for these testcases to run reliably, was to make sure that
the address used to spill the sigcontext on the process stack would not get
modified while running data_access_emulation(); this logic was eventually
fixed in r1.21, and nothing more is needed.
Thanks to Andrew Griffiths for pointing to my attention that the data fed to
sigreturn() was partially user-controllable, and that carefully crafted
signal handlers could use this behaviour as unprivileged kernel memory read
and write operations.
import upstream pkgconf regress
The Makefile is adapted to bsd.regress.mk from upstream's Makefile.lite
(also imported) in such a way that the diff is as small as possible, so
that it should be reasonably easy for me to keep it in sync with upstream
releases.