http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55969
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> 2013-01-14 14:09:53 UTC --- dnl See whether setcontext changes the value of TLS variables. AC_CACHE_CHECK([whether setcontext clobbers TLS variables], probably doesn't check what it should because of this, too.
