Fixed wrong declaration of zero sized char* array and signedness conversion errors using pointers. (C vs C++ issue.)
Modernized BOOL/TRUE/FALSE to bool/true/false globally. (Exceptions are Windows, Amiga and ancient (LHA and the like) code.)

As we are set on C99 (and C++11), bool/true/false should be enabled by default following the C99 Standard.
Where stdbool.h is either not available or not conforming to the standard, sysconfig.h will reflect this
and sysdeps.h will enable a replacement.
There is no valid reason to stay with the pre-C99 variants in the modern sources.
Add library path to QT libs for QT builds.
Fix crash on exit "free(): invalid pointer"