signal hander patch

[Andrew Haley]

Boehm, Hans writes:
 > Sorry about that.  Clearly I should have been more careful about PowerPC.
 > 
 > The problem with using syscall(SYS_sigaction ... ) is that it's
 > using effectively using a system call that's obsolete on Linux.  I
 > believe it exists on X86 only for backward compatibility, and
 > that's been the case for quite a while.  Glibc hasn't used it for a
 > while.  It doesn't exist on IA64.  It has been replaced by
 > SYS_rt_sigaction, which has a different (undocumented?) sequence of
 > arguments.  I would guess it won't exist in other new Linux ports.

All that this means is that we have some system-dependent code in
libgcj.  That's necessary because we're doing something that C++ and C
can't do.

 > Thus abstractly, it still makes marginally more sense to me to use
 > __libc_sigaction, since libc seems to be the only piece of code
 > that's really supposed to understand the system call calling
 > convention.

I disagree.  Why should kernel interfaces only be available to the C
library?

Andrew.