Cement ABI on clang for char16_t and char32_t.  Also fixed some comments in <iterator>.

llvm-svn: 113842
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 03976c1b625a7e14930215cb2a088fc9bb012481
diff --git a/lib/buildit b/lib/buildit
index 4b07113..0b51b2d 100755
--- a/lib/buildit
+++ b/lib/buildit
@@ -14,7 +14,7 @@
 
 if [ -z "$CXX" ]
 then
-	CXX=g++
+	CXX=clang++
 fi
 
 if [ -z $MACOSX_DEPLOYMENT_TARGET ]