LWG Issue 2087: iostream_category() and noexcept

llvm-svn: 192545
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: c3776b1ce07005952aeac4b96ce7f7447d0955d3
diff --git a/src/ios.cpp b/src/ios.cpp
index e79b328..bbe3c07 100644
--- a/src/ios.cpp
+++ b/src/ios.cpp
@@ -63,7 +63,7 @@
 }
 
 const error_category&
-iostream_category()
+iostream_category() _NOEXCEPT
 {
     static __iostream_category s;
     return s;