Fixed possible overflow issue with use of PDC_millisecs().

This function returns a long.  If that's 32 bits,  it will wrap
every 49.7 days.  It should be treated as a relative measurement
between two times.  In some of the code handling mouse events,
this wasn't the case,  and a precisely-timed mouse press could
cause a program to wait 49.7 days for the release.

Author: Bill-Gray

fb/pdckbd.c

@@ -56,12 +56,13 @@ static void _check_mouse( void)
    const int yper = ((PDC_orientation & 1) ? PDC_font_info.width : PDC_font_info.height);
    const int xmax = SP->cols * xper;
    const int ymax = SP->lines * yper;
-   long timeout = 0;
+   long prev_t = 0;
 
    _key_modifiers = PDC_get_modifiers( );
    if( _get_mouse_event( NULL))      /* already got events queued up */
       return;
-   while( (event = PDC_update_mouse( &button)) >= 0 || PDC_millisecs() < timeout)
+   while( (event = PDC_update_mouse( &button)) >= 0 ||
+                        (prev_t && PDC_millisecs() - prev_t < SP->mouse_wait))
       {
       int x, y;
 
@@ -88,13 +89,14 @@ static void _check_mouse( void)
             }
          else if( event == BUTTON_PRESSED || event == BUTTON_RELEASED)
             {
-            if( _add_raw_mouse_event( button - 1, event, modifs, x, y))
-               timeout = PDC_millisecs( ) + SP->mouse_wait;
+            if( _add_raw_mouse_event( button - 1, event, modifs, x, y)
+                        && SP->mouse_wait)
+               prev_t = PDC_millisecs( );
             else
                break;
             }
          }
-      else if( timeout)
+      else if( prev_t)
          napms( 10);
       }
    if( mx != PDC_mouse_x || my != PDC_mouse_y)

vt/pdckbd.c

@@ -433,9 +433,10 @@ int PDC_get_key( void)
                while( more_mouse)
                   {
                   const long t_end = PDC_millisecs( ) + SP->mouse_wait;
+                  long t;
 
-                  while( !check_key( NULL) && PDC_millisecs( ) < t_end)
-                     PDC_napms( 20);
+                  while( !check_key( NULL) && (t = t_end - PDC_millisecs( )) > 0)
+                     PDC_napms( t < 20 ? (int)t : 20);
                   more_mouse = (check_key( NULL) && PDC_get_key( ) == KEY_MOUSE);
                   }
                recursed = FALSE;

x11new/pdckbd.c

@@ -640,8 +640,8 @@ static bool check_key( int *c)
          const long t_end = PDC_millisecs( ) + SP->mouse_wait;
          long t;
 
-         while( (t = PDC_millisecs( )) < t_end && !XPending( dis))
-            napms( t_end - t < 20L ? (int)( t_end - t) : 20);
+         while( (t = t_end - PDC_millisecs( )) > 0 && !XPending( dis))
+            napms( t < 20L ? (int)t : 20);
          }
       if( !XPending( dis) || (!wait_for_more_mouse && _mlist_count))
          {