Add <sys/random.h>.
iOS 10 has <sys/random.h> with getentropy, glibc >= 2.25 has
<sys/random.h> with getentropy and getrandom. (glibc also pollutes
<unistd.h>, but that seems like a bad idea.)
Also, all supported devices now have kernels with the getrandom system
call.
We've had these available internally for a while, but it seems like the
time is ripe to expose them.
Bug: http://b/67014255
Test: ran tests
Change-Id: I76dde1e3a2d0bc82777eea437ac193f96964f138
diff --git a/libc/arch-arm64/syscalls/getrandom.S b/libc/arch-arm64/syscalls/getrandom.S
new file mode 100644
index 0000000..c8fe41f
--- /dev/null
+++ b/libc/arch-arm64/syscalls/getrandom.S
@@ -0,0 +1,14 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(getrandom)
+ mov x8, __NR_getrandom
+ svc #0
+
+ cmn x0, #(MAX_ERRNO + 1)
+ cneg x0, x0, hi
+ b.hi __set_errno_internal
+
+ ret
+END(getrandom)