patch 8.1.1805: au_did_filetype is declared twice

Problem:    Au_did_filetype is declared twice.
Solution:   Remove it from autocmd.c. (closes #4767)
diff --git a/src/autocmd.c b/src/autocmd.c
index be8e72d..19b5deb 100644
--- a/src/autocmd.c
+++ b/src/autocmd.c
@@ -240,16 +240,6 @@
 static char_u *deleted_augroup = NULL;
 
 /*
- * Set by the apply_autocmds_group function if the given event is equal to
- * EVENT_FILETYPE. Used by the readfile function in order to determine if
- * EVENT_BUFREADPOST triggered the EVENT_FILETYPE.
- *
- * Relying on this value requires one to reset it prior calling
- * apply_autocmds_group.
- */
-int au_did_filetype INIT(= FALSE);
-
-/*
  * The ID of the current group.  Group 0 is the default one.
  */
 static int current_augroup = AUGROUP_DEFAULT;
diff --git a/src/globals.h b/src/globals.h
index 6faee3b..92b2803 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -424,11 +424,18 @@
 
 EXTERN int	modified_was_set;		// did ":set modified"
 EXTERN int	did_filetype INIT(= FALSE);	// FileType event found
-EXTERN int	au_did_filetype INIT(= FALSE);
 EXTERN int	keep_filetype INIT(= FALSE);	// value for did_filetype when
 						// starting to execute
 						// autocommands
 
+// Set by the apply_autocmds_group function if the given event is equal to
+// EVENT_FILETYPE. Used by the readfile function in order to determine if
+// EVENT_BUFREADPOST triggered the EVENT_FILETYPE.
+//
+// Relying on this value requires one to reset it prior calling
+// apply_autocmds_group.
+EXTERN int	au_did_filetype INIT(= FALSE);
+
 // When deleting the current buffer, another one must be loaded.  If we know
 // which one is preferred, au_new_curbuf is set to it
 EXTERN bufref_T	au_new_curbuf INIT(= {NULL COMMA 0 COMMA 0});
diff --git a/src/version.c b/src/version.c
index d249d85..e2ebd89 100644
--- a/src/version.c
+++ b/src/version.c
@@ -774,6 +774,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1805,
+/**/
     1804,
 /**/
     1803,