configure: rewrote the support for languages in localisation

The code was moved to a dedicated file (wm_i18n.m4) to reduce the size of
configure.ac;

It now searches for gettext+libintl only if LINGUAS is specified, because
there is no need for them otherwise;

The list of supported locales is created automatically from the list of
files present in the source tree, so there won't be problem forgetting to
update the variables when a new language is added, or removed because
one is considered outdated;

The new syntax is now using as much as possible Autoconf's syntax to ensure
consistency and better portability;

Took opportunity to improve the language check loop to make it smaller and
to tell when a locale that the user asked for is not fully supported.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>

WPrefs.app/po/Makefile.am

@@ -1,6 +1,6 @@
 DOMAIN = WPrefs
 
-CATALOGS = @WPMOFILES@
+CATALOGS = @WPREFSMOFILES@
 
 nlsdir = $(NLSDIR)
 

configure.ac

@@ -411,16 +411,13 @@ dnl ==========
 AC_CHECK_PROG([PKGCONFIG], [pkg-config], [pkg-config])
 
 
-dnl gettext
-dnl =======
 
-dnl AM_GNU_GETTEXT
+dnl Internationalization
+dnl ====================
+dnl Detect the language for translations to be installed and check
+dnl that the gettext environment works
+WM_I18N_LANGUAGES
 
-INTLIBS=""
-
-AC_CHECK_FUNC(gettext, [HAVEGETTEXT="yes"], 
-	AC_CHECK_LIB(intl, gettext, [INTLIBS="-lintl" HAVEGETTEXT="yes"],
-			 INTLIBS="" ))
 
 AC_CHECK_PROG(XGETTEXT, xgettext, xgettext)
 
@@ -431,81 +428,6 @@ if test "$XGETTEXT" != ""; then
     fi
 fi
 
-if test "$LINGUAS" != ""; then
-    if test "$XGETTEXT" != "" -a "$HAVEGETTEXT" != ""; then
-        AC_DEFINE(I18N, 1, [Internationalization (I18N) support (set by configure)])
-        PO=""
-        echo "xgettext and gettext() exist; will build i18n support for $LINGUAS"
-    else
-        LINGUAS=""
-        PO=""
-        echo "xgettext and libintl.a don't both exist; will not build i18n support"
-    fi
-else
-    	INTLIBS=""
-	MOFILES=""
-	WPMOFILES=""
-	UTILMOFILES=""
-	PO=""
-fi
-
-
-dnl The Tower of Babel
-dnl ==================
-
-dnl List of supported locales
-dnl =========================
-supported_locales="be bg bs ca cs da de el es et fi fr gl hr hu hy it ja ko ms nl no pl pt ro ru sk sv tr zh_CN zh_TW"
-supported_wprefs_locales="bg ca cs de es et fi fr hr hu it ja ko nl pt ru sk zh_CN zh_TW"
-supported_wings_locales="bg ca cs de fr hu nl sk"
-supported_util_locales="de es fr nl pt"
-
-for lang in $LINGUAS; do
-	ok=0
-	for l in $supported_locales; do
-		if test "$l" = "$lang"; then
-			ok=1
-			break
-		fi
-	done
-	if test "$ok" = 1; then
-		MOFILES="$MOFILES $lang.mo"
-	else
-		echo "Locale $lang is not supported."
-	fi
-	ok=0
-	for l in $supported_wprefs_locales; do
-		if test "$l" = "$lang"; then
-			ok=1
-			break
-		fi
-	done
-	if test "$ok" = 1; then
-		WPMOFILES="$WPMOFILES $lang.mo"
-	fi
-	ok=0
-	for l in $supported_util_locales; do
-		if test "$l" = "$lang"; then
-			ok=1
-			break
-		fi
-	done
-	if test "$ok" = 1; then
-		UTILMOFILES="$UTILMOFILES $lang.mo"
-	fi
-	ok=0
-	for l in $supported_wings_locales; do
-		if test "$l" = "$lang"; then
-			ok=1
-			break
-		fi
-	done
-	if test "$ok" = 1; then
-		WINGSMOFILES="$WINGSMOFILES $lang.mo"
-	fi
-done
-
-
 dnl Added by Oliver - Support for NLSDIR option
 dnl ===========================================
 AC_ARG_WITH(nlsdir, AS_HELP_STRING([--with-nlsdir=PATH], [specify where the locale stuff should go]))
@@ -525,13 +447,7 @@ AC_ARG_WITH(menu-textdomain, AS_HELP_STRING([--with-menu-textdomain=DOMAIN], [sp
 	 fi])
 AC_SUBST(menutextdomain)
 
-AC_SUBST(INTLIBS)
 AC_SUBST(NLSDIR)
-AC_SUBST(MOFILES)
-AC_SUBST(WPMOFILES)
-AC_SUBST(UTILMOFILES)
-AC_SUBST(WINGSMOFILES)
-AC_SUBST(supported_locales)
 
 
 dnl ===========================================
@@ -995,18 +911,6 @@ AC_OUTPUT
 
 dnl Provide a summary of the config
 dnl ===============================
-if test "x$MOFILES" = "x"; then
-	mof=None
-else
-	mof=`echo $MOFILES`
-fi
-
-if test "x$MOFILES" = "x"; then
-	languages=None
-else
-	languages=`echo $MOFILES | sed 's/.mo//g'`
-fi
-
 echo
 echo "Window Maker was configured as follows:"
 echo
@@ -1019,11 +923,9 @@ echo "Supported graphic format libraries  :$supported_gfx"
 echo "Unsupported features                :$unsupported"
 echo "Antialiased text support in WINGs   : $xft"
 echo "Pango text layout support in WINGs  : $pango"
-echo "Translated message files to install : $mof"
+echo "Translated languages to support     :$supported_locales"
-dnl echo "Supported languages beside English  : $languages"
+AS_IF([test "x$supported_locales" != "x disabled"],
-if test "x$MOFILES" != "x"; then
+	[echo "Installation path for translations  : $NLSDIR" | sed -e 's|\$(prefix)|'"$prefix|"])
-	echo "Installation path for translations  : $NLSDIR" | sed -e 's|\$(prefix)|'"$prefix|"
-fi
 AS_IF([test "x$debug" = "xyes"],
     [AS_ECHO(["Debug enabled: CFLAGS = $CFLAGS"]) ])
 echo
@@ -1031,6 +933,9 @@ echo
 AS_IF([test "x$wm_cv_prog_cc_nestedfunc" != "xyes"],
     [AC_MSG_WARN([[Your compiler does not support Nested Function, work-around enabled]])])
 
+AS_IF([test "x$supported_locales" = "x"],
+    [AC_MSG_WARN([[No language from \$LINGUAS are supported]])])
+
 AS_IF([test "x$enable_jpeg" = xno], [dnl
     AS_ECHO(["WARNING   WARNING   WARNING   WARNING   WARNING   WARNING   WARNING"])
     AS_ECHO([])

m4/wm_i18n.m4

@@ -0,0 +1,94 @@
+# wm_i18n.m4 - Macros to check and enable translations in WindowMaker
+#
+# Copyright (c) 2014-2015 Christophe CURIS
+# Copyright (c) 2015 The Window Maker Tean
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; see the file COPYING.
+
+
+# WM_I18N_LANGUAGES
+# -----------------
+#
+# Detect which languages the user wants to be installed and check if
+# the gettext environment is available.
+#
+# The list of languages are provided through the environment variable
+# LINGUAS as a space-separated list of ISO 3166 country codes.
+# This list is checked against the list of currently available languages
+# the sources and a warning is issued if a language is not found.
+#
+# Support for internationalisation is disabled if the variable is empty
+# (or undefined)
+#
+# The variable 'supported_locales' is created to contain the list of
+# languages that will have been detected properly and will be installed
+AC_DEFUN_ONCE([WM_I18N_LANGUAGES],
+[AC_ARG_VAR([LINGUAS],
+    [list of language translations to support (I18N), use 'list' to get the list of supported languages, default: none])dnl
+AS_IF([test "x$LINGUAS" != "x"],
+    [wm_save_LIBS="$LIBS"
+     AC_SEARCH_LIBS([gettext], [intl], [],
+        [AC_MSG_ERROR([support for internationalization requested, but library for gettext not found])])
+     AS_IF([test "x$ac_cv_search_gettext" = "xnone required"],
+         [INTLIBS=""],
+         [INTLIBS="$ac_cv_search_gettext"])
+     AC_CHECK_FUNCS([gettext dgettext], [],
+        [AC_MSG_ERROR([support for internationalization requested, but gettext was not found])])
+     LIBS="$wm_save_LIBS"
+     dnl
+     dnl Environment is sane, let's continue
+     AC_DEFINE([I18N], [1], [Internationalization (I18N) support (set by configure)])
+     supported_locales=""
+
+     # This is the list of locales that our archive currently supports
+     wings_locales=" m4_esyscmd([ls WINGs/po/ | sed -n '/po$/{s,.po,,;p}' | tr '\n' ' '])"
+     wmaker_locales=" m4_esyscmd([ls po/ | sed -n '/po$/{s,.po,,;p}' | tr '\n' ' '])"
+     wprefs_locales=" m4_esyscmd([ls WPrefs.app/po/ | sed -n '/po$/{s,.po,,;p}' | tr '\n' ' '])"
+     util_locales=" m4_esyscmd([ls util/po/ | sed -n '/po$/{s,.po,,;p}' | tr '\n' ' '])"
+
+     # Check every language asked by user against these lists to know what to install
+     for lang in $LINGUAS; do
+         found=0
+         wm_missing=""
+         m4_foreach([REGION], [WINGs, wmaker, WPrefs, util],
+             [AS_IF([echo "$[]m4_tolower(REGION)[]_locales" | grep " $lang " > /dev/null],
+                 [m4_toupper(REGION)MOFILES="$[]m4_toupper(REGION)MOFILES $lang.mo"
+                  found=1],
+                 [wm_missing="$wm_missing, REGION"])
+             ])
+         # Locale has to be supported by at least one part to be reported in the end
+         # If it is not supported everywhere we just display a message to the user so
+         # that he knows about it
+         wm_missing="`echo "$wm_missing" | sed -e 's/^, //' `"
+         AS_IF([test $found = 1],
+             [supported_locales="$supported_locales $lang"
+              AS_IF([test "x$wm_missing" != "x"],
+                  [AC_MSG_WARN([locale $lang is not supported in $wm_missing])]) ],
+             [AC_MSG_WARN([locale $lang is not supported at all, ignoring])])
+     done
+],
+[INTLIBS=""
+ WINGSMOFILES=""
+ WMAKERMOFILES=""
+ WPREFSMOFILES=""
+ UTILMOFILES=""
+ supported_locales=" disabled"])
+dnl
+dnl The variables that are used in the Makefiles:
+AC_SUBST([INTLIBS])dnl
+AC_SUBST([WINGSMOFILES])dnl
+AC_SUBST([WMAKERMOFILES])dnl
+AC_SUBST([WPREFSMOFILES])dnl
+AC_SUBST([UTILMOFILES])dnl
+])

po/Makefile.am

@@ -2,7 +2,7 @@ DOMAIN = WindowMaker
 
 nlsdir      = $(NLSDIR)
 
-CATALOGS = @MOFILES@
+CATALOGS = @WMAKERMOFILES@
 
 CLEANFILES = $(CATALOGS) $(DOMAIN).pot