Reorganize llvmc code.

Move the code from 'llvmc/driver' into a new CompilerDriver library, and change
the build system accordingly. Makes it easier for projects using LLVM to build
their own llvmc-based drivers.

Tested with objdir != srcdir.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65821 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CompilerDriver/Error.h

@@ -0,0 +1,33 @@
+//===--- Error.h - The LLVM Compiler Driver ---------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open
+// Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  Exception classes for LLVMC.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVMC2_ERROR_H
+#define LLVM_TOOLS_LLVMC2_ERROR_H
+
+#include <stdexcept>
+
+namespace llvmc {
+
+  class error_code: public std::runtime_error {
+    int Code_;
+  public:
+    error_code (int c)
+      : std::runtime_error("Tool returned error code"), Code_(c)
+    {}
+
+    int code() const { return Code_; }
+  };
+
+}
+
+#endif //LLVM_TOOLS_LLVMC2_ERROR_H