printsiginfo: constify the first argument

* signal.c (printsiginfo): Make the first argument a pointer to a const type.
* defs.h (printsiginfo): Likewise.
(printsiginfo, printsiginfo_at): Always define these prototypes.
* configure.ac (AC_CHECK_TYPES): Remove siginfo_t, as HAVE_SIGINFO_T
is no longer used.
3 files changed