* configure.in, configure: enable dwarf2-exception-style
	exception handling on IA-64.
	* include/dwarf2-signal.h (MAKE_THROW_FRAME): Add for IA-64.
	(INIT_SEGV, INIT_FPE): Use __libc_sigaction instead of syscall.
	Add FIXME comment.

From-SVN: r51367