re PR other/3337 (build on linux-gnulibc1 fails: no sys/ucontext.h)

re PR other/3337 (build on linux-gnulibc1 fails: no sys/ucontext.h)

	PR other/3337
	PR bootstrap/6763
	PR bootstrap/8122
	* fixinc/inclhack.def (libc1_G_va_list): New fix.
	* fixinc/fixincl.x: Regenerate.
	* config/i386/linux.h: Move MD_FALLBACK_FRAME_STATE_FOR inside
	ifndef IN_LIBGCC2.  Wrap it together with signal.h and
	sys/ucontext.h inclusion in ifndef USE_GNULIBC_1.
	* configure.in (gcc_AC_CHECK_DECLS): Check vasprintf too.
	* config.in, configure: Regenerate.
	(Forgot to add PR markers.  Doh!)

From-SVN: r58514