Begin moving code from adb to libadb.

Much of adb is duplicated in bootable/recovery/minadb and fastboot.
Changes made to adb rarely get ported to the other two, so the trees
have diverged a bit. We'd like to stop this because it is a
maintenance nightmare, but the divergence makes this difficult to do
all at once. For now, we will start small by moving common files into
a static library. Hopefully some day we can get enough of adb in here
that we no longer need minadb.

Bug: 17626262
Change-Id: Ic8d5653bfcc0fec4e1acbece124402355084b864
diff --git a/adb/adb.h b/adb/adb.h
index a37fd5b..6ac4731 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -20,6 +20,7 @@
 #include <limits.h>
 
 #include "adb_trace.h"
+#include "fdevent.h"
 #include "transport.h"  /* readx(), writex() */
 
 #define MAX_PAYLOAD 4096