Revert "Revert "Update getentropy_linux.c from upstream.""

This reverts commit b3fbee449c314aee4bdc2f1720a931ea56c32f62.

Bug: http://b/27729263
Change-Id: I9d88ddb11466d203514ae805f4681c92e4b63c24
diff --git a/libc/NOTICE b/libc/NOTICE
index a2f2b0a..cdf29e3 100644
--- a/libc/NOTICE
+++ b/libc/NOTICE
@@ -5503,7 +5503,7 @@
 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 Emulation of getentropy(2) as documented at:
-http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man2/getentropy.2
+http://man.openbsd.org/getentropy.2
 
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