Auto merge of #3082 - devnexen:fbsd_signal_const, r=JohnTitor

adding specific freebsd signal constants

Author: bors

libc-test/semver/freebsd.txt

@@ -1111,7 +1111,10 @@ SIGEV_THREAD
 SIGEV_THREAD_ID
 SIGINFO
 SIGIO
+SIGLIBRT
+SIGLWP
 SIGSTKSZ
+SIGTHR
 SIOCGIFADDR
 SLIPDISC
 SOCKCREDSIZE

src/unix/bsd/freebsdlike/freebsd/mod.rs

@@ -3800,6 +3800,11 @@ pub const CPU_WHICH_CPUSET: ::c_int = 3;
 pub const CPU_WHICH_IRQ: ::c_int = 4;
 pub const CPU_WHICH_JAIL: ::c_int = 5;
 
+// sys/signal.h
+pub const SIGTHR: ::c_int = 32;
+pub const SIGLWP: ::c_int = SIGTHR;
+pub const SIGLIBRT: ::c_int = 33;
+
 const_fn! {
     {const} fn _ALIGN(p: usize) -> usize {
         (p + _ALIGNBYTES) & !_ALIGNBYTES