patch 7.4.1551
Problem: Cannot generate help tags in all doc directories.
Solution: Make ":helptags ALL" work.
diff --git a/src/proto/ex_cmds2.pro b/src/proto/ex_cmds2.pro
index 1f11774..14546b5 100644
--- a/src/proto/ex_cmds2.pro
+++ b/src/proto/ex_cmds2.pro
@@ -61,6 +61,7 @@
void ex_compiler(exarg_T *eap);
void ex_runtime(exarg_T *eap);
int source_runtime(char_u *name, int all);
+int do_in_path(char_u *path, char_u *name, int flags, void (*callback)(char_u *fname, void *ck), void *cookie);
int do_in_runtimepath(char_u *name, int all, void (*callback)(char_u *fname, void *ck), void *cookie);
void ex_packloadall(exarg_T *eap);
void ex_packadd(exarg_T *eap);