patch 8.1.0825: code for autocommands is mixed with file I/O code

Problem:    Code for autocommands is mixed with file I/O code.
Solution:   Move autocommand code to a separate file. (Yegappan Lakshmanan,
            closes #3863)
diff --git a/src/Make_dice.mak b/src/Make_dice.mak
index 2daa8d7..83614ca 100644
--- a/src/Make_dice.mak
+++ b/src/Make_dice.mak
@@ -27,6 +27,7 @@
 
 SRC = \
 	arabic.c \
+	autocmd.c \
 	blowfish.c \
 	buffer.c \
 	charset.c \
@@ -84,6 +85,7 @@
 	version.c
 
 OBJ =	o/arabic.o \
+	o/autocmd.o \
 	o/blowfish.o \
 	o/buffer.o \
 	o/charset.o \
@@ -161,6 +163,8 @@
 
 o/arabic.o:	arabic.c  $(SYMS)
 
+o/autocmd.o:	autocmd.c  $(SYMS)
+
 o/blowfish.o:	blowfish.c  $(SYMS)
 
 o/buffer.o:	buffer.c  $(SYMS)