patch 8.2.0320: no Haiku support

Problem:    No Haiku support.
Solution:   Add support for Haiku. (Emir Sari, closes #5605)

src/screen.c

@@ -2549,6 +2549,10 @@ retry:
 
     win_new_shellsize();    // fit the windows in the new sized shell
 
+#ifdef FEAT_GUI_HAIKU
+    vim_lock_screen();  // be safe, put it here
+#endif
+
     comp_col();		// recompute columns for shown command and ruler
 
     /*
@@ -2799,6 +2803,10 @@ give_up:
 #endif
     clear_TabPageIdxs();
 
+#ifdef FEAT_GUI_HAIKU
+    vim_unlock_screen();
+#endif
+
     entered = FALSE;
     --RedrawingDisabled;
 
@@ -3646,6 +3654,10 @@ screen_ins_lines(
 	clip_scroll_selection(-line_count);
 #endif
 
+#ifdef FEAT_GUI_HAIKU
+    vim_lock_screen();
+#endif
+
 #ifdef FEAT_GUI
     // Don't update the GUI cursor here, ScreenLines[] is invalid until the
     // scrolling is actually carried out.
@@ -3700,6 +3712,10 @@ screen_ins_lines(
 	}
     }
 
+#ifdef FEAT_GUI_HAIKU
+    vim_unlock_screen();
+#endif
+
     screen_stop_highlight();
     windgoto(cursor_row, cursor_col);
     if (clear_attr != 0)
@@ -3928,6 +3944,10 @@ screen_del_lines(
 	}
     }
 
+#ifdef FEAT_GUI_HAIKU
+    vim_unlock_screen();
+#endif
+
     if (screen_attr != clear_attr)
 	screen_stop_highlight();
     if (clear_attr != 0)