Can't include .hh sketch tab

[per1234]

Using Arduino IDE 1.6.13 Hourly Build 2016/10/03 06:51 with Windows 7 64 bit

@Chris--A added support for .hh and .hpp sketch files in #3485 however if I create a sketch tab with a .hh extension and then try to include that file from the sketch:

#include "hhtab.hh"

compilation fails:

fatal error: hhtab.hh: No such file or directory
 #include "hhtab.hh"

This problem doesn't occur with sketch tabs with the .hpp extension.

EDIT: originally reported at http://forum.arduino.cc/index.php?topic=427309

[facchinm]

To be merged with #5441 when moved to arduino-builder repo