noexcept applied to <random>.

llvm-svn: 160579
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 00586de436e092b4a699ae5e1f0b3723814f0e8b
diff --git a/src/random.cpp b/src/random.cpp
index 6140b74..97a40c5 100644
--- a/src/random.cpp
+++ b/src/random.cpp
@@ -40,7 +40,7 @@
 }
 
 double
-random_device::entropy() const
+random_device::entropy() const _NOEXCEPT
 {
     return 0;
 }