patch 8.0.1663: cannot build without multi-byte feature

Problem:    Cannot build without multi-byte feature.
Solution:   Add #ifdef.
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index b013004..046ef3c 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -5308,6 +5308,7 @@
     return p;
 }
 
+#if defined(FEAT_MBYTE) || defined(PROTO)
     int
 get_bad_opt(char_u *p, exarg_T *eap)
 {
@@ -5319,6 +5320,7 @@
 	eap->bad_char = *p;
     return FAIL;
 }
+#endif
 
 /*
  * Get "++opt=arg" argument.
diff --git a/src/version.c b/src/version.c
index 4b9761f..4d19b47 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1663,
+/**/
     1662,
 /**/
     1661,