patch 8.2.3886: can define autocmd for every event by using "au!"

Problem:    Can define autocmd for every event by using "au!".
Solution:   Check if a command is present also for "au!".
diff --git a/src/autocmd.c b/src/autocmd.c
index 789dde1..9b6a5d0 100644
--- a/src/autocmd.c
+++ b/src/autocmd.c
@@ -967,7 +967,7 @@
     last_group = AUGROUP_ERROR;		// for listing the group name
     if (*arg == '*' || *arg == NUL || *arg == '|')
     {
-	if (!forceit && *cmd != NUL)
+	if (*cmd != NUL)
 	    emsg(_(e_cannot_define_autocommands_for_all_events));
 	else
 	    for (event = (event_T)0; (int)event < NUM_EVENTS;
diff --git a/src/testdir/test_arglist.vim b/src/testdir/test_arglist.vim
index ca7e2f8..9f9957a 100644
--- a/src/testdir/test_arglist.vim
+++ b/src/testdir/test_arglist.vim
@@ -581,7 +581,7 @@
 
 func Test_clear_arglist_in_all()
   n 0 00 000 0000 00000 000000
-  au! * 0 n 0
+  au WinNew 0 n 0
   call assert_fails("all", "E1156")
   au! *
 endfunc
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index 4bdb8dc..b6f621d 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
Binary files differ
diff --git a/src/version.c b/src/version.c
index b7b5441..14e65f1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3886,
+/**/
     3885,
 /**/
     3884,