OpenCL: Improve vector printf warnings

The vector modifier is considered separate, so
don't treat it as a conversion specifier.

This is still not warning on some cases, like
using a type that isn't a valid vector element.

Fixes bug 39652

llvm-svn: 348084
diff --git a/clang/lib/AST/FormatStringParsing.h b/clang/lib/AST/FormatStringParsing.h
index 91fab15..9da829a 100644
--- a/clang/lib/AST/FormatStringParsing.h
+++ b/clang/lib/AST/FormatStringParsing.h
@@ -41,6 +41,10 @@
                       FormatSpecifier &CS, const char *Start,
                       const char *&Beg, const char *E);
 
+bool ParseVectorModifier(FormatStringHandler &H,
+                         FormatSpecifier &FS, const char *&Beg, const char *E,
+                         const LangOptions &LO);
+
 /// Returns true if a LengthModifier was parsed and installed in the
 /// FormatSpecifier& argument, and false otherwise.
 bool ParseLengthModifier(FormatSpecifier &FS, const char *&Beg, const char *E,