Disable the warning for missing prototypes for OpenCL kernels. Includes testcase.

llvm-svn: 160766
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 12444e5..7233fc7 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -7509,6 +7509,10 @@
   if (FD->isFunctionTemplateSpecialization())
     return false;
 
+  // Don't warn for OpenCL kernels.
+  if (FD->hasAttr<OpenCLKernelAttr>())
+    return false;
+  
   bool MissingPrototype = true;
   for (const FunctionDecl *Prev = FD->getPreviousDecl();
        Prev; Prev = Prev->getPreviousDecl()) {