Implement kexec_load decoding

* kexec.c: New file.
* linux/kexec.h: Likewise.
* Makefile.am (strace_SOURCES): Add kexec.c.
(EXTRA_DIST): Add linux/kexec.h.
* linux/dummy.h (sys_kexec_load): Remove.
* linux/syscall.h (sys_kexec_load): New prototype.
5 files changed