Use proper internal macros for BSD sig_t and GNU sighandler_t.
sigaltstack and friends are XSI even in SUSv4 but in glibc are
nonetheless handled as POSIX.1-2008 (not 2001).
The requirement for the ucontext_t typedef in signal.h was XSI prior to
POSIX.1-2008.
Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
* libc/include/signal.h (SIG_IGN, SIG_DFL, SIG_ERR): Change
to use _sig_func_ptr type casted constants.
(_sig_func_ptr): Typedef moved to sys/signal.h.
* libc/include/sys/signal.h (_sig_func_ptr): Typedef added.
For __rtems, use POSIX definition, otherwise default to ANSI.
* libc/sys/linux/sys/signal.h (_sig_func_ptr): Typedef added.