[libdazzle] i18n: setup gettext from library static constructor

[Christian Hergert <chergert src gnome org>]

commit 477c097aa05f6aef38fa19d0e2f59df1ca17ff71
Author: Christian Hergert <chergert redhat com>
Date:   Mon Jan 20 10:20:06 2020 -0800

    i18n: setup gettext from library static constructor
    
    Fixes #52

 src/dzl-init.c     | 41 ++++++++++++++++++++++++
 src/gconstructor.h | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/meson.build    |  1 +
 3 files changed, 136 insertions(+)
---
diff --git a/src/dzl-init.c b/src/dzl-init.c
new file mode 100644
index 0000000..9ae276a
--- /dev/null
+++ b/src/dzl-init.c
@@ -0,0 +1,41 @@
+/* dzl-init.c
+ *
+ * Copyright 2020 Christian Hergert <chergert redhat com>
+ *
+ * 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 3 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.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include "config.h"
+
+#include <glib/gi18n.h>
+
+#include "gconstructor.h"
+
+#if defined (G_HAS_CONSTRUCTORS)
+# ifdef G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA
+#  pragma G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(dzl_init_ctor)
+# endif
+G_DEFINE_CONSTRUCTOR(dzl_init_ctor)
+#else
+# error Your platform/compiler is missing constructor support
+#endif
+
+static void
+dzl_init_ctor (void)
+{
+  bindtextdomain (GETTEXT_PACKAGE, LOCALEDIR);
+  bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
+}
diff --git a/src/gconstructor.h b/src/gconstructor.h
new file mode 100644
index 0000000..df98f83
--- /dev/null
+++ b/src/gconstructor.h
@@ -0,0 +1,94 @@
+/*
+  If G_HAS_CONSTRUCTORS is true then the compiler support *both* constructors and
+  destructors, in a sane way, including e.g. on library unload. If not you're on
+  your own.
+
+  Some compilers need #pragma to handle this, which does not work with macros,
+  so the way you need to use this is (for constructors):
+
+  #ifdef G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA
+  #pragma G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(my_constructor)
+  #endif
+  G_DEFINE_CONSTRUCTOR(my_constructor)
+  static void my_constructor(void) {
+   ...
+  }
+
+*/
+
+#ifndef __GTK_DOC_IGNORE__
+
+#if  __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+
+#define G_HAS_CONSTRUCTORS 1
+
+#define G_DEFINE_CONSTRUCTOR(_func) static void __attribute__((constructor)) _func (void);
+#define G_DEFINE_DESTRUCTOR(_func) static void __attribute__((destructor)) _func (void);
+
+#elif defined (_MSC_VER) && (_MSC_VER >= 1500)
+/* Visual studio 2008 and later has _Pragma */
+
+#define G_HAS_CONSTRUCTORS 1
+
+#define G_DEFINE_CONSTRUCTOR(_func) \
+  static void _func(void); \
+  static int _func ## _wrapper(void) { _func(); return 0; } \
+  __pragma(section(".CRT$XCU",read)) \
+  __declspec(allocate(".CRT$XCU")) static int (* _array ## _func)(void) = _func ## _wrapper;
+
+#define G_DEFINE_DESTRUCTOR(_func) \
+  static void _func(void); \
+  static int _func ## _constructor(void) { atexit (_func); return 0; } \
+  __pragma(section(".CRT$XCU",read)) \
+  __declspec(allocate(".CRT$XCU")) static int (* _array ## _func)(void) = _func ## _constructor;
+
+#elif defined (_MSC_VER)
+
+#define G_HAS_CONSTRUCTORS 1
+
+/* Pre Visual studio 2008 must use #pragma section */
+#define G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA 1
+#define G_DEFINE_DESTRUCTOR_NEEDS_PRAGMA 1
+
+#define G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(_func) \
+  section(".CRT$XCU",read)
+#define G_DEFINE_CONSTRUCTOR(_func) \
+  static void _func(void); \
+  static int _func ## _wrapper(void) { _func(); return 0; } \
+  __declspec(allocate(".CRT$XCU")) static int (*p)(void) = _func ## _wrapper;
+
+#define G_DEFINE_DESTRUCTOR_PRAGMA_ARGS(_func) \
+  section(".CRT$XCU",read)
+#define G_DEFINE_DESTRUCTOR(_func) \
+  static void _func(void); \
+  static int _func ## _constructor(void) { atexit (_func); return 0; } \
+  __declspec(allocate(".CRT$XCU")) static int (* _array ## _func)(void) = _func ## _constructor;
+
+#elif defined(__SUNPRO_C)
+
+/* This is not tested, but i believe it should work, based on:
+ * http://opensource.apple.com/source/OpenSSL098/OpenSSL098-35/src/fips/fips_premain.c
+ */
+
+#define G_HAS_CONSTRUCTORS 1
+
+#define G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA 1
+#define G_DEFINE_DESTRUCTOR_NEEDS_PRAGMA 1
+
+#define G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(_func) \
+  init(_func)
+#define G_DEFINE_CONSTRUCTOR(_func) \
+  static void _func(void);
+
+#define G_DEFINE_DESTRUCTOR_PRAGMA_ARGS(_func) \
+  fini(_func)
+#define G_DEFINE_DESTRUCTOR(_func) \
+  static void _func(void);
+
+#else
+
+/* constructors not supported for this compiler */
+
+#endif
+
+#endif /* __GTK_DOC_IGNORE__ */
diff --git a/src/meson.build b/src/meson.build
index d8c2afa..b7e298d 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -80,6 +80,7 @@ libdazzle_sources = [
   libdazzle_public_sources,
   libdazzle_private_sources,
   libdazzle_resources,
+  'dzl-init.c',
 ]
 
 libdazzle_deps = [