Switch from calling obsolete sig{block,setmask} to directly using the
sigprocmask syscall.
abort() can't return, so simplify the call, and use the internal name to
avoid the PLT.

no-return observation by Miod Vallat, testing by aoyama@

Stop supporting longjmperror(); it's not used, not portable, and the checks
longjmp performs can't really be relied upon, even after we got rid of the
false positives...

ok millert@ deraadt@

Do provide hidden _libc_* aliases for sig{block,setmask} and use them in
the ASM *setjmp implementations.
Skip the PLT when calling them on amd64 (other archs to do this after testing)

ok miod@

PIC-related code should follow the #ifdef __PIC__ line, not the #else line.
Doh!

Add END() directives to the various functions.
Make the code PIC-aware when necessary (i.e. invoke other functions through
the PLT, and access global data through the GOT). No change for non-PIC
compilation.

Switch m88k ports to ELF.

Fix almost ten-years old bug in siglongjmp(), which would not restore a signal
mask of zero (because of flawed logic assuming finding zero in the sigjmp_buf
signal mask means sigsetjmp was invoked with a zero `savemask' argument).

While there, clean comments of all *{set,long}jmp routines, and shave a few
instructions by using bcnd insead of cmp + bb to test for zero values.

Passes the regress tests, and now devel/libsigsegv configure siglongjmp test
will not spin (this test is however flawed as it expects a signal handler
declared as running on the sigaltstack and `returning' through siglongjmp to
be invoked on the signal stack the next time the signal is raised).

zap rcsid.
okay deraadt@ (tested them all)

Use less stack space for temporary storage and C code invocation, after
the ABI change.

In the never-ending story of *setjmp bugs, fix a typo preventing
sigsetjmp(foo, !0) to work. Sigh.

In setjmp() and sigsetjmp(), be sure to return with r14 and r15 unchanged, as
they are part of the call preserved register set, and gcc -O relies upon this.

Fix the *longjmp() behaviour - it is legal to reuse a jmp_buf several times.
Gets us a working perl 5.8.

Get static rcsid correctly, better style for .S files, trim whitespace.

Fix *longjmp() return values.

Typos

Fix license and conformance with man page.

correted sigsetjmp, setjump. Fixed MACHINE_ARCH vs. MACHINE stuff.