Fix and include

Author: mgreter

src/file.hpp

@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "sass/context.h"
+#include "sass/functions.h"
 #include "ast_fwd_decl.hpp"
 
 namespace Sass {

src/stylesheet.hpp

@@ -5,6 +5,7 @@
 // __EXTENSIONS__ fix on Solaris.
 #include "sass.hpp"
 
+#include "sass/functions.h"
 #include "ast_fwd_decl.hpp"
 #include "extender.hpp"
 #include "file.hpp"