Eli Zaretskii wrote:

>> Sorry, that is not true (mistakenly thought, that fopen won't work with
>> windows paths). Then i should really rebuild ispell with LIBDIR set to
>> native path and it will work with Emacs.
>
> I think you don't even need that.  You need to set ISPELL_DICTDIR in
> the environment to point to that directory.
>
> (The reason I didn't suggest this earlier is that I didn't know Cygwin
> can fopen Windows-style absolute file names.)

Actually that won't work with current ispell.el, because LIBRARYVAR is 
completely ignored and dictionaries searched only in LIBDIR (though it 
can be overridden by LIBRARYVAR).

Fixed this and other (-d with an absolute path) issues in attached patch.

Below is a explanatory test:

(require 'ispell)
ispell

;; cygwin ispell reports its LIBDIR as
(ispell-check-version)
"/usr/local/lib"

;; and it's not a correct/existing windows path
(file-exists-p "/usr/local/lib")
nil

(shell-command-to-string "cygpath -w /usr/local/lib")
"C:\\cygwin64\\usr\\local\\lib
"

;; so ispell.el still can not see valid/installed dictionaries
(shell-command-to-string "ls -l /usr/local/lib")
"total 1126
lrwxrwxrwx 1 Admin None      16 Jul 29 01:38 american.hash -> 
americanmed.hash
-rw-r--r-- 1 Admin None 1125408 Jul 29 01:38 americanmed.hash
-rw-r--r-- 1 Admin None   24095 Jul 29 01:38 english.aff
lrwxrwxrwx 1 Admin None      16 Jul 29 01:38 english.hash -> 
americanmed.hash
"
(ispell-valid-dictionary-list)
("default")


;; Though now we can add dictionaries explicitly (-d with an absolute path)
ispell-local-dictionary-alist
nil

(add-to-list 'ispell-local-dictionary-alist
	     '("american" "[A-Za-z]" "[^A-Za-z]" "[']" nil
	       ("-d" "c:/cygwin64/usr/local/lib/american.hash") nil iso-8859-1))
(("american" "[A-Za-z]" "[^A-Za-z]" "[']" nil ("-d" 
"c:/cygwin64/usr/local/lib/american.hash") nil iso-8859-1))


(add-to-list 'ispell-local-dictionary-alist
	     '("english" "[A-Za-z]" "[^A-Za-z]" "[']" nil
	       ("-d" "c:/cygwin64/usr/local/lib/english.hash") nil iso-8859-1))
(("english" "[A-Za-z]" "[^A-Za-z]" "[']" nil ("-d" 
"c:/cygwin64/usr/local/lib/english.hash") nil iso-8859-1) ("american" 
"[A-Za-z]" "[^A-Za-z]" "[']" nil ("-d" 
"c:/cygwin64/usr/local/lib/american.hash") nil iso-8859-1))

(ispell-valid-dictionary-list)
("american" "english" "default")

;; or we can set ispell LIBRARYVAR (default: ISPELL_DICTDIR) environment 
variable
(setq ispell-local-dictionary-alist nil)
nil
(ispell-valid-dictionary-list)
("default")

(setenv "ISPELL_DICTDIR" "c:/cygwin64/usr/local/lib")
"c:/cygwin64/usr/local/lib"

(setq ispell-library-directory (ispell-check-version))
"c:/cygwin64/usr/local/lib"

(ispell-valid-dictionary-list)
("english" "american" "default")