Availability of sprintf_s is a C standard library thing, not a compiler thing.

Our clang/win build currently uses MSVS's C library, so it doesn't have
snprintf but it does have sprintf_s.

BUG=chromium:82385
LOG=n
R=jochen@chromium.org

Review URL: https://codereview.chromium.org/370823002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22224 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ostreams.cc

@@ -6,7 +6,7 @@
 
 #include "src/ostreams.h"
 
-#if V8_CC_MSVC
+#if V8_OS_WIN
 #define snprintf sprintf_s
 #endif