sigaction(2): *at system calls are async-signal safe.

lib/libc/sys/sigaction.2

@@ -375,12 +375,16 @@ Base Interfaces:
 .Fn execle ,
 .Fn execv ,
 .Fn execve ,
+.Fn faccessat ,
 .Fn fchdir ,
 .Fn fchmod ,
+.Fn fchmodat ,
 .Fn fchown ,
+.Fn fchownat ,
 .Fn fcntl ,
 .Fn fork ,
 .Fn fstat ,
+.Fn fstatat ,
 .Fn fsync ,
 .Fn ftruncate ,
 .Fn getegid ,
@@ -396,13 +400,18 @@ Base Interfaces:
 .Fn getuid ,
 .Fn kill ,
 .Fn link ,
+.Fn linkat ,
 .Fn listen ,
 .Fn lseek ,
 .Fn lstat ,
 .Fn mkdir ,
+.Fn mkdirat ,
 .Fn mkfifo ,
+.Fn mkfifoat ,
 .Fn mknod ,
+.Fn mknodat ,
 .Fn open ,
+.Fn openat ,
 .Fn pause ,
 .Fn pipe ,
 .Fn poll ,
@@ -411,10 +420,12 @@ Base Interfaces:
 .Fn raise ,
 .Fn read ,
 .Fn readlink ,
+.Fn readlinkat ,
 .Fn recv ,
 .Fn recvfrom ,
 .Fn recvmsg ,
 .Fn rename ,
+.Fn renameat ,
 .Fn rmdir ,
 .Fn select ,
 .Fn send ,
@@ -442,6 +453,7 @@ Base Interfaces:
 .Fn socketpair ,
 .Fn stat ,
 .Fn symlink ,
+.Fn symlinkat ,
 .Fn tcdrain ,
 .Fn tcflow ,
 .Fn tcflush ,
@@ -455,6 +467,7 @@ Base Interfaces:
 .Fn umask ,
 .Fn uname ,
 .Fn unlink ,
+.Fn unlinkat ,
 .Fn utime ,
 .Fn wait ,
 .Fn waitpid ,
@@ -543,6 +556,7 @@ but planned to be:
 .Pp
 Extension Interfaces:
 .Pp
+.Fn futimesat ,
 .Fn strlcpy ,
 .Fn strlcat .
 .Pp