* Use a proper namespace.

* Optimise header file usage a bit.
* Compile the parser as C++.

src/libexpr/parser.hh

@@ -4,6 +4,9 @@
 #include "eval.hh"
 
 
+namespace nix {
+
+
 /* Parse a Nix expression from the specified file.  If `path' refers
    to a directory, the "/default.nix" is appended. */
 Expr parseExprFromFile(EvalState & state, Path path);
@@ -13,4 +16,7 @@ Expr parseExprFromString(EvalState & state, const string & s,
     const Path & basePath);
 
 
+}
+
+
 #endif /* !__PARSER_H */