Add runtime translation support

Add support for gettext-based runtime translations. Enabled with
configure switch --enable-translation (no autodetection). Note that no
translation files are installed yet.

configure

@@ -216,6 +216,7 @@ Installation directories:
   --mandir=DIR           directory for installing man pages [PREFIX/share/man]
   --confdir=DIR          directory for installing configuration files
                          [PREFIX/etc/mplayer]
+  --localedir=DIR        directory for locale tree [PREFIX/share/locale]
   --libdir=DIR           directory for object code libraries [PREFIX/lib]
   --codecsdir=DIR        directory for binary codecs [LIBDIR/codecs]
   --win32codecsdir=DIR   directory for Windows DLLs [LIBDIR/codecs]
@@ -398,6 +399,7 @@ Audio output:
   --disable-select       disable using select() on the audio device [enable]
 
 Language options:
+  --enable-translation   enable support for translated output [disable]
   --charset=charset      convert the console messages to this character set
   --language-doc=lang    language to use for the documentation [en]
   --language-man=lang    language to use for the man pages [en]
@@ -656,6 +658,7 @@ _largefiles=yes
 #language=en
 _shm=auto
 _linux_devfs=no
+_translation=no
 _charset="UTF-8"
 _dynamic_plugins=no
 _crash_debug=no
@@ -733,6 +736,9 @@ for ac_option do
   --realcodecsdir=*)
     _realcodecsdir=$(echo $ac_option | cut -d '=' -f 2)
     ;;
+  --localedir=*)
+    _localedir=$(echo $ac_option | cut -d '=' -f 2)
+    ;;
 
   --with-install=*)
     _install=$(echo $ac_option | cut -d '=' -f 2 )
@@ -843,6 +849,8 @@ for ac_option do
   --disable-debug)
     _debug=
     ;;
+  --enable-translation)              _translation=yes           ;;
+  --disable-translation)             _translation=no            ;;
   --enable-runtime-cpudetection)    _runtime_cpudetection=yes   ;;
   --disable-runtime-cpudetection)   _runtime_cpudetection=no    ;;
   --enable-cross-compile)           _cross_compile=yes          ;;
@@ -1265,6 +1273,7 @@ test -z "$_datadir" && _datadir="$_prefix/share/mplayer"
 test -z "$_mandir"  && _mandir="$_prefix/share/man"
 test -z "$_confdir" && _confdir="$_prefix/etc/mplayer"
 test -z "$_libdir"  && _libdir="$_prefix/lib"
+test -z "$_localedir"  && _localedir="$_prefix/share/locale"
 
 # Determine our OS name and CPU architecture
 if test -z "$_target" ; then
@@ -2825,6 +2834,14 @@ fi
 echores "$_langinfo"
 
 
+echocheck "translation support"
+if test "$_translation" = yes; then
+  def_translation="#define CONFIG_TRANSLATION 1"
+else
+  def_translation="#undef CONFIG_TRANSLATION"
+fi
+echores "$_translation"
+
 echocheck "language"
 # Set preferred languages, "all" uses English as main language.
 test -z "$language" && language=$LINGUAS
@@ -7840,6 +7857,7 @@ DATADIR = \$(DESTDIR)$_datadir
 LIBDIR = \$(DESTDIR)$_libdir
 MANDIR = \$(DESTDIR)$_mandir
 CONFDIR = \$(DESTDIR)$_confdir
+LOCALEDIR = \$(DESTDIR)$_localedir
 
 AR = $_ar
 AS = $_cc
@@ -8137,6 +8155,9 @@ cat > $TMPH << EOF
 #define MPLAYER_DATADIR "$_datadir"
 #define MPLAYER_CONFDIR "$_confdir"
 #define MPLAYER_LIBDIR "$_libdir"
+#define MPLAYER_LOCALEDIR "$_localedir"
+
+$def_translation
 
 /* definitions needed by included libraries */
 #define HAVE_INTTYPES_H 1

mp_msg.c

@@ -5,6 +5,11 @@
 
 #include "config.h"
 
+#ifdef CONFIG_TRANSLATION
+#include <locale.h>
+#include <libintl.h>
+#endif
+
 #ifdef CONFIG_ICONV
 #include <iconv.h>
 #include <errno.h>
@@ -77,6 +82,14 @@ void mp_msg_init(void){
     if (!mp_msg_charset)
       mp_msg_charset = get_term_charset();
 #endif
+#ifdef CONFIG_TRANSLATION
+    textdomain("mplayer");
+    char *localedir = getenv("MPLAYER_LOCALEDIR");
+    if (localedir == NULL && strlen(MPLAYER_LOCALEDIR))
+        localedir = MPLAYER_LOCALEDIR;
+    bindtextdomain("mplayer", localedir);
+    bind_textdomain_codeset("mplayer", "UTF-8");
+#endif
 }
 
 int mp_msg_test(int mod, int lev)
@@ -224,8 +237,63 @@ void mp_msg(int mod, int lev, const char *format, ...)
     va_end(va);
 }
 
-
 char *mp_gtext(const char *string)
 {
+#ifdef CONFIG_TRANSLATION
+    /* gettext expects the global locale to be set with
+     * setlocale(LC_ALL, ""). However doing that would suck for a
+     * couple of reasons (locale stuff is badly designed and sucks in
+     * general).
+     *
+     * First setting the locale, especially LC_CTYPE, changes the
+     * behavior of various C functions and we don't want that - we
+     * want isalpha() for example to always behave like in the C
+     * locale.
+
+     * Second, there is no way to enforce a sane character set. All
+     * strings inside MPlayer must always be in utf-8, not in the
+     * character set specified by the system locale which could be
+     * something different and completely insane. The locale system
+     * lacks any way to say "set LC_CTYPE to utf-8, ignoring the
+     * default system locale if it specifies something different". We
+     * could try to work around that flaw by leaving LC_CTYPE to the C
+     * locale and only setting LC_MESSAGES (which is the variable that
+     * must be set to tell gettext which language to translate
+     * to). However if we leave LC_MESSAGES set then things like
+     * strerror() may produce completely garbled output when they try
+     * to translate their results but then try to convert some
+     * translated non-ASCII text to the character set specified by
+     * LC_CTYPE which would still be in the C locale (this doesn't
+     * affect gettext itself because it supports specifying the
+     * character set directly with bind_textdomain_codeset()).
+     *
+     * So the only solution (at leat short of trying to work around
+     * things possibly producing non-utf-8 output) is to leave all the
+     * locale variables unset. Note that this means it's not possible
+     * to get translated output from any libraries we call if they
+     * only rely on the broken locale system to specify the language
+     * to use; this is the case with libc for example.
+     *
+     * The locale changing below is rather ugly, but hard to avoid.
+     * gettext doesn't support specifying the translation target
+     * directly, only through locale.
+     * The main actual problem this could cause is interference with
+     * other threads; that could be avoided with thread-specific
+     * locale changes, but such functionality is less standard and I
+     * think it's not worth adding pre-emptively unless someone sees
+     * an actual problem case.
+     */
+    setlocale(LC_MESSAGES, "");
+    string = gettext(string);
+    setlocale(LC_MESSAGES, "C");
+#endif
     return string;
 }
+
+void mp_tmsg(int mod, int lev, const char *format, ...)
+{
+    va_list va;
+    va_start(va, format);
+    mp_msg_va(mod, lev, mp_gtext(format), va);
+    va_end(va);
+}

mp_msg.h

@@ -118,12 +118,12 @@ int mp_msg_test(int mod, int lev);
 #include "config.h"
 
 char *mp_gtext(const char *string);
-#define mp_tmsg mp_msg
 
 void mp_msg_va(int mod, int lev, const char *format, va_list va);
 
 #ifdef __GNUC__
 void mp_msg(int mod, int lev, const char *format, ... ) __attribute__ ((format (printf, 3, 4)));
+void mp_tmsg(int mod, int lev, const char *format, ... ) __attribute__ ((format (printf, 3, 4)));
 #   ifdef MP_DEBUG
 #      define mp_dbg(mod,lev, args... ) mp_msg(mod, lev, ## args )
 #   else
@@ -131,6 +131,7 @@ void mp_msg(int mod, int lev, const char *format, ... ) __attribute__ ((format (
 #   endif
 #else // not GNU C
 void mp_msg(int mod, int lev, const char *format, ... );
+void mp_tmsg(int mod, int lev, const char *format, ...)
 #   ifdef MP_DEBUG
 #      define mp_dbg(mod,lev, ... ) mp_msg(mod, lev, __VA_ARGS__)
 #   else