Improve robustness of new string-collation code.

* configure.ac (newlocale): Check for this, not for uselocale.
* src/sysdep.c (LC_COLLATE, LC_COLLATE_MASK, freelocale, locale_t)
(newlocale, wcscoll_l): Define substitutes for platforms that
lack them, so as to simplify the mainline code.
(str_collate): Simplify the code by assuming the above definitions.
Use wcscoll_l, not uselocale, as uselocale is too fragile.  For
example, the old version left the Emacs in the wrong locale if
wcscoll reported an error.  Use 'int', not ptrdiff_t, for the int
result.  Report an error if newlocale fails.

Fixes: debbugs:18051

1 files changed, 12 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index d7066b823b9..8a32bc27b0b 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,15 @@
+2014-08-27  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Improve robustness of new string-collation code (Bug#18051).
+        * sysdep.c (LC_COLLATE, LC_COLLATE_MASK, freelocale, locale_t)
+        (newlocale, wcscoll_l): Define substitutes for platforms that
+        lack them, so as to simplify the mainline code.
+        (str_collate): Simplify the code by assuming the above definitions.
+        Use wcscoll_l, not uselocale, as uselocale is too fragile.  For
+        example, the old version left the Emacs in the wrong locale if
+        wcscoll reported an error.  Use 'int', not ptrdiff_t, for the int
+        result.  Report an error if newlocale fails.
+
 2014-08-27  Michael Albinus  <michael.albinus@gmx.de>
 
         * lisp.h (str_collate):