Turn cl::values() (for enum) from a vararg function to using C++ variadic template

The core of the change is supposed to be NFC, however it also fixes
what I believe was an undefined behavior when calling:

 va_start(ValueArgs, Desc);

with Desc being a StringRef.

Differential Revision: https://reviews.llvm.org/D25342

llvm-svn: 283671
diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index 7df1507..add3573 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -24,8 +24,7 @@
                clEnumValN(TargetLibraryInfoImpl::Accelerate, "Accelerate",
                           "Accelerate framework"),
                clEnumValN(TargetLibraryInfoImpl::SVML, "SVML",
-                          "Intel SVML library"),
-               clEnumValEnd));
+                          "Intel SVML library")));
 
 StringRef const TargetLibraryInfoImpl::StandardNames[LibFunc::NumLibFuncs] = {
 #define TLI_DEFINE_STRING