patch 8.2.0901: formatting CJK text isn't optimal

Problem:    Formatting CJK text isn't optimal.
Solution:   Properly break CJK lines. (closes #3875)
diff --git a/src/proto/mbyte.pro b/src/proto/mbyte.pro
index 7b8c4fe..79af974 100644
--- a/src/proto/mbyte.pro
+++ b/src/proto/mbyte.pro
@@ -52,6 +52,9 @@
 int latin_head_off(char_u *base, char_u *p);
 int dbcs_screen_head_off(char_u *base, char_u *p);
 int utf_head_off(char_u *base, char_u *p);
+int utf_eat_space(int cc);
+int utf_allow_break_before(int cc);
+int utf_allow_break(int cc, int ncc);
 void mb_copy_char(char_u **fp, char_u **tp);
 int mb_off_next(char_u *base, char_u *p);
 int mb_tail_off(char_u *base, char_u *p);