types: Add missing functional include

std::function is not found with a GCC 7.2 runtime.

Tested: Built repository with GCC 7.2
Change-Id: I4f122039e7708a2cb9f785210e49c7d22abb8510
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/types.hpp b/types.hpp
index e650d3c..46ce020 100644
--- a/types.hpp
+++ b/types.hpp
@@ -2,6 +2,7 @@
 
 #include <ifaddrs.h>
 
+#include <functional>
 #include <list>
 #include <string>
 #include <vector>