Using std::string requires `#include <string>', says gcc-2.95.3.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7833 91177308-0d34-0410-b5e6-96231b3b80d8

support/tools/TableGen/CodeGenWrappers.h

@@ -12,6 +12,7 @@
 
 #include "llvm/CodeGen/ValueTypes.h"
 #include <iosfwd>
+#include <string>
 #include <vector>
 class Record;
 class RecordKeeper;

utils/TableGen/CodeGenTarget.h

@@ -12,6 +12,7 @@
 
 #include "llvm/CodeGen/ValueTypes.h"
 #include <iosfwd>
+#include <string>
 #include <vector>
 class Record;
 class RecordKeeper;

utils/TableGen/CodeGenWrappers.h

@@ -12,6 +12,7 @@
 
 #include "llvm/CodeGen/ValueTypes.h"
 #include <iosfwd>
+#include <string>
 #include <vector>
 class Record;
 class RecordKeeper;