Add support for "first" and "last" execution modes

1 files changed, 2 insertions, 1 deletions

diff --git a/build/path b/build/path
index 9644b6a..5c492f7 100644
--- a/build/path
+++ b/build/path
@@ -7,8 +7,9 @@
 
 #include <string>
 #include <ostream>
-#include <utility> // move
+#include <utility>    // move
 #include <exception>
+#include <functional> // hash
 
 namespace build
 {