Move sigreturn/rt_sigreturn parser to a separate file

* sigreturn.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* defs.h (sprintsigmask_n): New prototype.
(tprintsigmask_addr): New macro.
* signal.c (sprintsigmask_n): Make global.
(tprintsigmask_addr): Remove.
(sys_sigreturn): Move to sigreturn.c.
4 files changed