patch 9.0.0282: a nested timout stops the previous timeout

Problem:    A nested timout stops the previous timeout.
Solution:   Ignore any nested timeout.

src/evalfunc.c

@@ -9176,6 +9176,7 @@ do_searchpair(
 
 theend:
 #ifdef FEAT_RELTIME
+    if (time_limit > 0)
 	disable_regexp_timeout();
 #endif
     vim_free(pat2);

src/regexp.c

@@ -51,18 +51,33 @@ toggle_Magic(int x)
 }
 
 #ifdef FEAT_RELTIME
+static int timeout_nesting = 0;
+
+/*
+ * Start a timer that will cause the regexp to abort after "msec".
+ * This doesn't work well recursively.  In case it happens anyway, the first
+ * set timeout will prevail, nested ones are ignored.
+ * The caller must make sure there is a matching disable_regexp_timeout() call!
+ */
     void
 init_regexp_timeout(long msec)
 {
+    if (timeout_nesting == 0)
 	timeout_flag = start_timeout(msec);
+    ++timeout_nesting;
 }
 
     void
 disable_regexp_timeout(void)
+{
+    if (timeout_nesting == 0)
+	iemsg("disable_regexp_timeout() called without active timer");
+    else if (--timeout_nesting == 0)
     {
 	stop_timeout();
 	timeout_flag = &dummy_timeout_flag;
     }
+}
 #endif
 
 /*

src/version.c

@@ -707,6 +707,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    282,
 /**/
     281,
 /**/