Drop unused variables and code.
pan-view.c: In function ‘pan_grid_build’:
pan-view.c:753:14: attention : variable ‘ah’ set but not used [-Wunused-but-set-variable]
pan-view.c:753:10: attention : variable ‘aw’ set but not used [-Wunused-but-set-variable]
pan-view.c: In function ‘pan_window_key_press_cb’:
pan-view.c:1217:2: attention : suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
pan-view.c:1271:8: attention : variable ‘n’ set but not used [-Wunused-but-set-variable]
pan-view.c: In function ‘pan_window_set_dnd_data’:
pan-view.c:2939:8: attention : unused variable ‘len’ [-Wunused-variable]
pan-view.c:2938:10: attention : unused variable ‘text’ [-Wunused-variable]