Add required includes in "oid.h" The file was previously failing to be included stand-alone.
diff --git a/src/git2/oid.h b/src/git2/oid.h
index 7c95342..5cac46f 100644
--- a/src/git2/oid.h
+++ b/src/git2/oid.h
@@ -25,6 +25,9 @@
#ifndef INCLUDE_git_oid_h__
#define INCLUDE_git_oid_h__
+#include "common.h"
+#include "types.h"
+
/**
* @file git2/oid.h
* @brief Git object id routines