More minor updates, fighting with Travis

Author: p-ranav

src/config.cpp

@@ -1,4 +1,5 @@
 #include <cppgit2/config.hpp>
+#include <functional>
 
 namespace cppgit2 {
 

src/diff.cpp

@@ -1,4 +1,5 @@
 #include <cppgit2/diff.hpp>
+#include <functional>
 
 namespace cppgit2 {
 

src/index.cpp

@@ -1,4 +1,5 @@
 #include <cppgit2/repository.hpp>
+#include <functional>
 
 namespace cppgit2 {
 

src/odb.cpp

@@ -1,5 +1,6 @@
 #include <cppgit2/odb.hpp>
 using namespace cppgit2;
+#include <functional>
 
 odb::odb() : c_ptr_(nullptr), owner_(ownership::user) {
   git_odb_new(&c_ptr_); // owned by user

src/pack_builder.cpp

@@ -1,4 +1,5 @@
 #include <cppgit2/pack_builder.hpp>
+#include <functional>
 
 namespace cppgit2 {
 

src/patch.cpp

@@ -1,5 +1,6 @@
 #include <cppgit2/patch.hpp>
 using namespace cppgit2;
+#include <functional>
 
 patch::patch() : c_ptr_(nullptr), owner_(ownership::libgit2) {}
 

src/repository.cpp

@@ -1,4 +1,5 @@
 #include <cppgit2/repository.hpp>
+#include <functional>
 
 namespace cppgit2 {
 

src/revwalk.cpp

@@ -1,5 +1,6 @@
 #include <cppgit2/repository.hpp>
 using namespace cppgit2;
+#include <functional>
 
 revwalk::revwalk()
     : done_(false), c_ptr_(nullptr), owner_(ownership::libgit2) {}

src/tree.cpp

@@ -1,4 +1,5 @@
 #include <cppgit2/repository.hpp>
+#include <functional>
 
 namespace cppgit2 {
 

src/tree_builder.cpp

@@ -1,4 +1,5 @@
 #include <cppgit2/tree_builder.hpp>
+#include <functional>
 
 namespace cppgit2 {