Move TableGen's parser and entry point into a library

This is the first step towards splitting LLVM and Clang's tblgen executables.

llvm-svn: 140951
diff --git a/llvm/utils/TableGen/FixedLenDecoderEmitter.cpp b/llvm/utils/TableGen/FixedLenDecoderEmitter.cpp
index a3255a0..02b966a 100644
--- a/llvm/utils/TableGen/FixedLenDecoderEmitter.cpp
+++ b/llvm/utils/TableGen/FixedLenDecoderEmitter.cpp
@@ -16,7 +16,7 @@
 
 #include "FixedLenDecoderEmitter.h"
 #include "CodeGenTarget.h"
-#include "Record.h"
+#include "llvm/TableGen/Record.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"