Export some email and pretty-printing functions

These will be used for generating the cover letter in addition to the
patch emails.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/log-tree.h b/log-tree.h
index b33f7cd..0cc9344 100644
--- a/log-tree.h
+++ b/log-tree.h
@@ -13,5 +13,7 @@
 int log_tree_opt_parse(struct rev_info *, const char **, int);
 void show_log(struct rev_info *opt, const char *sep);
 void show_decorations(struct commit *commit);
+void log_write_email_headers(struct rev_info *opt, const char *name,
+			     const char **subject_p, const char **extra_headers_p);
 
 #endif