patch 7.4.993

Problem:    Test 87 is flaky on AppVeyor.
Solution:   Reduce the minimum background thread count.

Author: brammool

src/testdir/test86.in

@@ -370,7 +370,9 @@ EOF
 :sleep 1
 :py t.running = False
 :py t.join()
-:py l[0] = t.t > 7  # check if the background thread is working
+:" Check if the background thread is working.  Count should be 10, but on a
+:" busy system (AppVeyor) it can be much lower.
+:py l[0] = t.t > 4
 :py del time
 :py del threading
 :py del t

src/testdir/test87.in

@@ -367,7 +367,9 @@ EOF
 :sleep 1
 :py3 t.running = False
 :py3 t.join()
-:py3 l[0] = t.t > 7  # check if the background thread is working
+:" Check if the background thread is working.  Count should be 10, but on a
+:" busy system (AppVeyor) it can be much lower.
+:py3 l[0] = t.t > 4
 :py3 del time
 :py3 del threading
 :py3 del t

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    993,
 /**/
     992,
 /**/