localename: Update comments regarding Cygwin

[Bruno Haible]

Cygwin has uselocale() etc. since version 2.6. See
https://cygwin.com/ml/cygwin-announce/2016-08/msg00095.html

Let me update the documentation.


2018-12-18  Bruno Haible  <address@hidden>

        localename: Update comments regarding Cygwin.
        * lib/localename.c: Update comment.
        * doc/posix-functions/uselocale.texi: Update platforms list.
        * doc/posix-functions/newlocale.texi: Likewise.
        * doc/posix-functions/duplocale.texi: Likewise.
        * doc/posix-functions/freelocale.texi: Likewise.

diff --git a/doc/posix-functions/duplocale.texi 
b/doc/posix-functions/duplocale.texi
index 000300b..7be505c 100644
--- a/doc/posix-functions/duplocale.texi
+++ b/doc/posix-functions/duplocale.texi
@@ -21,5 +21,5 @@ Portability problems not fixed by Gnulib:
 @itemize
 @item
 This function is missing on many platforms:
-Mac OS X 10.3, FreeBSD 9.0, NetBSD 5.0, OpenBSD 6.1, Minix 3.1.8, AIX 6.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11.3, Cygwin, mingw, MSVC 14, Interix 
3.5, BeOS, Android 4.4.
+Mac OS X 10.3, FreeBSD 9.0, NetBSD 5.0, OpenBSD 6.1, Minix 3.1.8, AIX 6.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11.3, Cygwin 2.5.x, mingw, MSVC 14, 
Interix 3.5, BeOS, Android 4.4.
 @end itemize
diff --git a/doc/posix-functions/freelocale.texi 
b/doc/posix-functions/freelocale.texi
index e4ff00f..515baae 100644
--- a/doc/posix-functions/freelocale.texi
+++ b/doc/posix-functions/freelocale.texi
@@ -14,5 +14,5 @@ Portability problems not fixed by Gnulib:
 @itemize
 @item
 This function is missing on many platforms:
-Mac OS X 10.3, FreeBSD 9.0, NetBSD 5.0, OpenBSD 6.1, Minix 3.1.8, AIX 6.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11.3, Cygwin, mingw, MSVC 14, Interix 
3.5, BeOS, Android 4.4.
+Mac OS X 10.3, FreeBSD 9.0, NetBSD 5.0, OpenBSD 6.1, Minix 3.1.8, AIX 6.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11.3, Cygwin 2.5.x, mingw, MSVC 14, 
Interix 3.5, BeOS, Android 4.4.
 @end itemize
diff --git a/doc/posix-functions/newlocale.texi 
b/doc/posix-functions/newlocale.texi
index 376f7e8..02a5c6d 100644
--- a/doc/posix-functions/newlocale.texi
+++ b/doc/posix-functions/newlocale.texi
@@ -14,7 +14,7 @@ Portability problems not fixed by Gnulib:
 @itemize
 @item
 This function is missing on many platforms:
-Mac OS X 10.3, FreeBSD 9.0, NetBSD 5.0, OpenBSD 6.1, Minix 3.1.8, AIX 6.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11.3, Cygwin, mingw, MSVC 14, Interix 
3.5, BeOS, Android 4.4.
+Mac OS X 10.3, FreeBSD 9.0, NetBSD 5.0, OpenBSD 6.1, Minix 3.1.8, AIX 6.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11.3, Cygwin 2.5.x, mingw, MSVC 14, 
Interix 3.5, BeOS, Android 4.4.
 @item
 This function is useless because the @code{locale_t} type contains basically
 no information on some platforms:
diff --git a/doc/posix-functions/uselocale.texi 
b/doc/posix-functions/uselocale.texi
index 2d8b947..1343214 100644
--- a/doc/posix-functions/uselocale.texi
+++ b/doc/posix-functions/uselocale.texi
@@ -14,7 +14,7 @@ Portability problems not fixed by Gnulib:
 @itemize
 @item
 This function is missing on many platforms:
-Mac OS X 10.3, FreeBSD 9.0, NetBSD 5.0, OpenBSD 6.1, Minix 3.1.8, AIX 6.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11.3, Cygwin, mingw, MSVC 14, Interix 
3.5, BeOS, Android 4.4.
+Mac OS X 10.3, FreeBSD 9.0, NetBSD 5.0, OpenBSD 6.1, Minix 3.1.8, AIX 6.1, 
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11.3, Cygwin 2.5.x, mingw, MSVC 14, 
Interix 3.5, BeOS, Android 4.4.
 @item
 This function is useless because the @code{locale_t} type contains basically
 no information on some platforms:
diff --git a/lib/localename.c b/lib/localename.c
index 28b3d61..735f427 100644
--- a/lib/localename.c
+++ b/lib/localename.c
@@ -2629,7 +2629,7 @@ get_lcid (const char *locale_name)
 #endif
 
 
-#if HAVE_GOOD_USELOCALE /* glibc, Mac OS X, FreeBSD >= 9.1, AIX >= 7,
+#if HAVE_GOOD_USELOCALE /* glibc, Mac OS X, FreeBSD >= 9.1, AIX >= 7, Cygwin 
>= 2.6,
                            Solaris 11 OpenIndiana, or Solaris >= 11.4  */
 
 /* Simple hash set of strings.  We don't want to drag in lots of hash table