diff -r 9d349a94ebbc -r 8250f31b2b8c tex.el
--- a/tex.el	Thu Nov 30 00:32:49 2017 +0900
+++ b/tex.el	Thu Nov 30 01:43:51 2017 +0900
@@ -2720,13 +2720,9 @@
     (let* ((exit-status 1)
 	   (args `(,@(if program `("--progname" ,program))
 		   "--expand-path"
-		   ;; It seems that kpsewhich accepts semicolon as
-		   ;; path delimiter even on non-w32 platform and
-		   ;; converts it to colon if necessary.
-		   ;; Quote from texmf.cnf of TeXLive 2017:
-		   ;; "In this file, either ; or : can be used to
-		   ;; separate path components."
-		   ,(mapconcat #'identity vars ";")))
+		   ,(concat "{"
+			    (mapconcat #'identity vars ",")
+			    "}")))
 	   (path-list (ignore-errors
 			(with-output-to-string
 			  (setq exit-status