Add `sigset64_t` and accompanying functions.
This doesn't address `struct sigaction` and `sigaction`. That will
come later.
Bug: http://b/72493232
Test: ran tests
Change-Id: I4134346757ce3a4dac6feae413361cec16223386
diff --git a/libc/include/sys/signalfd.h b/libc/include/sys/signalfd.h
index 315622c..2337cd7 100644
--- a/libc/include/sys/signalfd.h
+++ b/libc/include/sys/signalfd.h
@@ -37,6 +37,7 @@
__BEGIN_DECLS
int signalfd(int __fd, const sigset_t* __mask, int __flags) __INTRODUCED_IN(18);
+int signalfd64(int __fd, const sigset64_t* __mask, int __flags) __INTRODUCED_IN(28);
__END_DECLS