Add GSLC_USE_TSLIB parameter to LINUX Makefile - Should mean that users no longer need to modify the Makefile variable   GSLC_LDLIB_EXTRA for tslib mode.
Add GSLC_USE_TSLIB parameter to LINUX Makefile
- Should mean that users no longer need to modify the Makefile variable
  GSLC_LDLIB_EXTRA for tslib mode.

ImpulseAdventure/GUIslice,ImpulseAdventure/GUIslice