New FTBFS with GCC 6 and C++11 dialect

Hi all, I noticed during current builgs, on Ubuntu 16.10 (Yakkety) and now also on Debian 9 (Stretch) was changed the default compiler to GCC6. This brings the number of new FTBFS. That's why I started to concentrate on these FTBFS. Note - for this reason the packages for Yakkety in Preliminary Stable Builds are now inconsistent. As a first, of course, I started with tdelibs. Most were simple conflict signed / unsigned char or int. However, one serious problem is here. In the 'kjs' and 'tdehtml/ecma' is used HashEntry structure that contains the item 'value' of type short int - see 'kjs/lookup.h'. Into this item was stored values DOM::NodeFilter::ShowCode::SHOW_ALL = 0xFFFFFFFF (see tdehtml/dom/dom2_traversal.h) and kjs event CHANGE with value 32768 (see tdehtml/ecma/kjs_events.cpp). Both are therefore outside the range of short int. Changing the type of 'value' in HashEntry from short to long would apparently cause a change in ABI - kjs/lookup.h is part of the public includes. That's why I made the change values 0xFFFFFFFF and 32768 to -1. I think that GCC compilers version less than 6 will store these values in the same way. Therefore, I believe that the proposed patch would not cause problems == can be pushed. What is your opinion? Cheers -- Slávek