wrong signal.h

> cat sigtissue.c
#include <signal.h>
int main(int argc, char **argv)
{
        sig_t T = (sig_t)0;
        return 0;
}
> gcc --version
gcc.exe (Rev2, Built by MSYS2 project) 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

> gcc -o sigtissue sigtissue.c
sigtissue.c: In function 'main':
sigtissue.c:5:9: error: unknown type name 'sig_t'; did you mean 'size_t'?
    5 |         sig_t T = (sig_t)0;
      |         ^~~~~
      |         size_t
sigtissue.c:5:20: error: 'sig_t' undeclared (first use in this function); did you mean 'size_t'?
    5 |         sig_t T = (sig_t)0;
      |                    ^~~~~
      |                    size_t
sigtissue.c:5:20: note: each undeclared identifier is reported only once for each function it appears in
sigtissue.c:5:26: error: expected ',' or ';' before numeric constant
    5 |         sig_t T = (sig_t)0;
      |                          ^