patch 8.0.1276: key lost when window closed in exit callback

Problem:    Typed key is lost when the terminal window is closed in exit
            callback. (Gabriel Barta)
Solution:   When the current window changes bail out of the wait loop. (closes
            #2302)
diff --git a/src/misc2.c b/src/misc2.c
index 4d4d947..63d9e81 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -6300,6 +6300,8 @@
     void
 parse_queued_messages(void)
 {
+    win_T *old_curwin = curwin;
+
     /* For Win32 mch_breakcheck() does not check for input, do it here. */
 # if defined(WIN32) && defined(FEAT_JOB_CHANNEL)
     channel_handle_events(FALSE);
@@ -6324,6 +6326,11 @@
     /* Check if any jobs have ended. */
     job_check_ended();
 # endif
+
+    /* If the current window changed we need to bail out of the waiting loop.
+     * E.g. when a job exit callback closes the terminal window. */
+    if (curwin != old_curwin)
+	ins_char_typebuf(K_IGNORE);
 }
 #endif
 
diff --git a/src/terminal.c b/src/terminal.c
index c6b3860..4c58397 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -38,8 +38,6 @@
  * in tl_scrollback are no longer used.
  *
  * TODO:
- * - Termdebug: issue #2154 might be avoided by adding -quiet to gdb?
- *   patch by Christian, 2017 Oct 23.
  * - in GUI vertical split causes problems.  Cursor is flickering. (Hirohito
  *   Higashi, 2017 Sep 19)
  * - double click in Window toolbar starts Visual mode (but not always?).
@@ -1581,8 +1579,12 @@
 
 	c = term_vgetc();
 	if (!term_use_loop())
+	{
 	    /* job finished while waiting for a character */
+	    if (c != K_IGNORE)
+		vungetc(c);
 	    break;
+	}
 	if (c == K_IGNORE)
 	    continue;
 
diff --git a/src/version.c b/src/version.c
index abac386..39bad6c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1276,
+/**/
     1275,
 /**/
     1274,