Don't allow ALT-Direction to work when maximized

With maximized windows, unexpected behaviour occured when the program
resized itself, then the window manager minimized/restored the window
Should address SF bugs #18 and #13

src/conio/sdl_con.c

@@ -824,6 +824,9 @@ void sdl_video_event_thread(void *data)
 						     ev.key.keysym.sym == SDLK_UP ||
 						     ev.key.keysym.sym == SDLK_DOWN)) {
 							int w, h;
+
+							// Don't allow ALT-DIR to change size when maximized...
+							if ((sdl.GetWindowFlags(win) & SDL_WINDOW_MAXIMIZED) == 0) {
 								pthread_mutex_lock(&vstatlock);
 								w = cvstat.winwidth;
 								h = cvstat.winheight;
@@ -871,6 +874,7 @@ void sdl_video_event_thread(void *data)
 									cvstat.winheight = h;
 								}
 								pthread_mutex_unlock(&vstatlock);
+							}
 							break;
 						}
 					}

src/conio/sdlfuncs.c

@@ -198,6 +198,10 @@ int load_sdl_funcs(struct sdlfuncs *sdlf)
 		xp_dlclose(sdl_dll);
 		return(-1);
 	}
+	if((sdlf->GetWindowFlags=xp_dlsym(sdl_dll, SDL_GetWindowFlags))==NULL) {
+		xp_dlclose(sdl_dll);
+		return(-1);
+	}
 #ifndef STATIC_SDL
 	{
 		int (HACK_HACK_HACK *ra)(char *name, Uint32 style, void *hInst);

src/conio/sdlfuncs.h

@@ -55,6 +55,7 @@ struct sdlfuncs {
 	void (HACK_HACK_HACK *SetCursor)	(SDL_Cursor *curs);
 	void (HACK_HACK_HACK *FreeCursor)	(SDL_Cursor *curs);
 	void(HACK_HACK_HACK *free)	(void *);
+	Uint32(HACK_HACK_HACK *GetWindowFlags)	(SDL_Window * window);
 	int	gotfuncs;
 };