patch 9.1.0568: Cannot expand paths from 'cdpath' setting

Problem:  Cannot expand paths from 'cdpath' setting
          (Daniel Hahler)
Solution: Implement 'cdpath' completion, add the new 'dir_in_path'
          completion type (LemonBoy)

fixes #374
closes: #15205

Signed-off-by: LemonBoy <thatlemon@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/findfile.pro b/src/proto/findfile.pro
index 9560101..1c28221 100644
--- a/src/proto/findfile.pro
+++ b/src/proto/findfile.pro
@@ -12,7 +12,7 @@
 char_u *file_name_in_line(char_u *line, int col, int options, long count, char_u *rel_fname, linenr_T *file_lnum);
 char_u *find_file_name_in_path(char_u *ptr, int len, int options, long count, char_u *rel_fname);
 int vim_ispathlistsep(int c);
-void uniquefy_paths(garray_T *gap, char_u *pattern);
+void uniquefy_paths(garray_T *gap, char_u *pattern, char_u *path_option);
 int expand_in_path(garray_T *gap, char_u *pattern, int flags);
 void simplify_filename(char_u *filename);
 void f_simplify(typval_T *argvars, typval_T *rettv);