Add include/ to the Makefile include path.

The applypatch heaaders were recently moved to the include/ directory.
This patch reflects that change in the Makefile.

Bug: None
TEST=sudo emerge imgdiff

Change-Id: I0bf3f991b5e0c98054033c5939ed69b3e3c827a9
diff --git a/applypatch/Makefile b/applypatch/Makefile
index de6d426..fb49843 100644
--- a/applypatch/Makefile
+++ b/applypatch/Makefile
@@ -14,7 +14,7 @@
 
 # This file is for building imgdiff in Chrome OS.
 
-CPPFLAGS += -iquote..
+CPPFLAGS += -iquote.. -Iinclude
 CXXFLAGS += -std=c++11 -O3 -Wall -Werror
 LDLIBS += -lbz2 -lz