updated for version 7.3.535
Problem:    Many #ifdefs for MB_MAXBYTES.
Solution:   Also define MB_MAXBYTES without the +multi_byte feature.  Fix
            places where the buffer didn't include space for a NUL byte.
diff --git a/src/getchar.c b/src/getchar.c
index 606d9a2..aea8d10 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -723,7 +723,7 @@
     int				c;
 #ifdef FEAT_MBYTE
     int				n;
-    char_u			buf[MB_MAXBYTES];
+    char_u			buf[MB_MAXBYTES + 1];
     int				i;
 #endif
 
@@ -1072,7 +1072,7 @@
     int	    c;
 {
 #ifdef FEAT_MBYTE
-    char_u	buf[MB_MAXBYTES];
+    char_u	buf[MB_MAXBYTES + 1];
 #else
     char_u	buf[4];
 #endif
@@ -1547,7 +1547,7 @@
     int		c, c2;
 #ifdef FEAT_MBYTE
     int		n;
-    char_u	buf[MB_MAXBYTES];
+    char_u	buf[MB_MAXBYTES + 1];
     int		i;
 #endif
 
@@ -4335,11 +4335,7 @@
     int		scol;		/* starting column of the abbr. */
     int		j;
     char_u	*s;
-#ifdef FEAT_MBYTE
     char_u	tb[MB_MAXBYTES + 4];
-#else
-    char_u	tb[4];
-#endif
     mapblock_T	*mp;
 #ifdef FEAT_LOCALMAP
     mapblock_T	*mp2;