On Darwin, the string header file isn't 64-bit clean. The use of

"-Wshorten-64-to-32 -Werror" will cause a failure when compiling this complex
program:

#include <string>

class Path {
  mutable std::string path;
public:
  bool operator == (const Path &that) {
    return path == that.path;
  }
};

Using strcmp gets us past this annoying error.

llvm-svn: 51218