patch 9.1.0312: heredocs are not supported for :commands

Problem:  heredocs are not supported for :commands
          (@balki)
Solution: Add heredoc support
          (Yegappan Lakshmanan)

fixes: #14491
closes: #14528

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/charset.pro b/src/proto/charset.pro
index a747319..a4f6c45 100644
--- a/src/proto/charset.pro
+++ b/src/proto/charset.pro
@@ -61,6 +61,7 @@
 int vim_toupper(int c);
 int vim_tolower(int c);
 char_u *skiptowhite(char_u *p);
+char_u *skiptowhite_or_nl(char_u *p);
 char_u *skiptowhite_esc(char_u *p);
 long getdigits(char_u **pp);
 long getdigits_quoted(char_u **pp);