Add strsignal(3) to unix
This does not add sys_siglist because the docs specify that the function
should be used instead, whenever possible.
@@ -538,6 +538,7 @@ extern "C" {
pub fn strerror(n: c_int) -> *mut c_char;
pub fn strtok(s: *mut c_char, t: *const c_char) -> *mut c_char;
pub fn strxfrm(s: *mut c_char, ct: *const c_char, n: size_t) -> size_t;
+ pub fn strsignal(sig: c_int) -> *mut c_char;
pub fn wcslen(buf: *const wchar_t) -> size_t;
pub fn wcstombs(
dest: *mut c_char,
