add NSIG constant

glibc defines this constant as "the total number of signals defined.
Since the signal numbers are allocated consecutively, NSIG is also one
greater than the largest defined signal number."

Author: fiveop

src/sys/signal.rs

@@ -41,6 +41,8 @@ pub use self::signal::{
     SIGWINCH,
     SIGUSR1,
     SIGUSR2,
+
+    NSIG,
 };
 
 pub use self::signal::SockFlag;
@@ -102,6 +104,8 @@ pub mod signal {
     pub const SIGSYS:       libc::c_int = 31;
     pub const SIGUNUSED:    libc::c_int = 31;
 
+    pub const NSIG:         libc::c_int = 32;
+
     // This definition is not as accurate as it could be, {pid, uid, status} is
     // actually a giant union. Currently we're only interested in these fields,
     // however.
@@ -188,6 +192,8 @@ pub mod signal {
     pub const SIGXCPU:      libc::c_int = 30;
     pub const SIGFSZ:       libc::c_int = 31;
 
+    pub const NSIG:         libc::c_int = 32;
+
     // This definition is not as accurate as it could be, {pid, uid, status} is
     // actually a giant union. Currently we're only interested in these fields,
     // however.
@@ -266,6 +272,8 @@ pub mod signal {
     pub const SIGUSR1:      libc::c_int = 30;
     pub const SIGUSR2:      libc::c_int = 31;
 
+    pub const NSIG:         libc::c_int = 32;
+
     #[cfg(any(target_os = "macos", target_os = "ios", target_os = "openbsd"))]
     pub type sigset_t = u32;
     #[cfg(target_os = "freebsd")]