Basic: import SmallString<> into clang namespace

(I was going to fix the TODO about DenseMap too, but
that would break self-host right now. See PR11922.)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149799 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPExpressions.cpp b/lib/Lex/PPExpressions.cpp
index 4ce48e0..c4ab143 100644
--- a/lib/Lex/PPExpressions.cpp
+++ b/lib/Lex/PPExpressions.cpp
@@ -197,7 +197,7 @@
     PP.Diag(PeekTok, diag::err_pp_expected_value_in_expr);
     return true;
   case tok::numeric_constant: {
-    llvm::SmallString<64> IntegerBuffer;
+    SmallString<64> IntegerBuffer;
     bool NumberInvalid = false;
     StringRef Spelling = PP.getSpelling(PeekTok, IntegerBuffer, 
                                               &NumberInvalid);
@@ -251,7 +251,7 @@
   case tok::wide_char_constant: {   // L'x'
   case tok::utf16_char_constant:    // u'x'
   case tok::utf32_char_constant:    // U'x'
-    llvm::SmallString<32> CharBuffer;
+    SmallString<32> CharBuffer;
     bool CharInvalid = false;
     StringRef ThisTok = PP.getSpelling(PeekTok, CharBuffer, &CharInvalid);
     if (CharInvalid)