[gtk/wip/carlosg/include-constructors-header] gdk: Include copy of glib/gconstructor.h

[Carlos Garnacho <carlosg src gnome org>]

commit 65d9b7ee864a1c0102cb590c516a80dea4659925
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Mar 17 21:29:59 2019 +0100

    gdk: Include copy of glib/gconstructor.h
    
    This is named gdkconstructor.h to avoid any possible conflicts. This fixes
    the current usages of G_HAS_CONSTRUCTORS, as that header is not installed
    by glib.

 gdk/gdk.c                 |   2 +
 gdk/gdkconstructor.h      | 120 ++++++++++++++++++++++++++++++++++++++++++++++
 gtk/gtkapplication-dbus.c |   2 +
 3 files changed, 124 insertions(+)
---
diff --git a/gdk/gdk.c b/gdk/gdk.c
index 6c69f1a050..e094b3465a 100644
--- a/gdk/gdk.c
+++ b/gdk/gdk.c
@@ -33,6 +33,8 @@
 
 #include "gdk-private.h"
 
+#include "gdkconstructor.h"
+
 #ifndef HAVE_XCONVERTCASE
 #include "gdkkeysyms.h"
 #endif
diff --git a/gdk/gdkconstructor.h b/gdk/gdkconstructor.h
new file mode 100644
index 0000000000..dccb0314c5
--- /dev/null
+++ b/gdk/gdkconstructor.h
@@ -0,0 +1,120 @@
+/*
+  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
+
+/* We do some weird things to avoid the constructors being optimized
+ * away on VS2015 if WholeProgramOptimization is enabled. First we
+ * make a reference to the array from the wrapper to make sure its
+ * references. Then we use a pragma to make sure the wrapper function
+ * symbol is always included at the link stage. Also, the symbols
+ * need to be extern (but not dllexport), even though they are not
+ * really used from another object file.
+ */
+
+/* We need to account for differences between the mangling of symbols
+ * for Win32 (x86) and x64 programs, as symbols on Win32 are prefixed
+ * with an underscore but symbols on x64 are not.
+ */
+#ifdef _WIN64
+#define G_MSVC_SYMBOL_PREFIX ""
+#else
+#define G_MSVC_SYMBOL_PREFIX "_"
+#endif
+
+#define G_DEFINE_CONSTRUCTOR(_func) G_MSVC_CTOR (_func, G_MSVC_SYMBOL_PREFIX)
+#define G_DEFINE_DESTRUCTOR(_func) G_MSVC_DTOR (_func, G_MSVC_SYMBOL_PREFIX)
+
+#define G_MSVC_CTOR(_func,_sym_prefix) \
+  static void _func(void); \
+  extern int (* _array ## _func)(void);              \
+  int _func ## _wrapper(void) { _func(); g_slist_find (NULL,  _array ## _func); return 0; } \
+  __pragma(comment(linker,"/include:" _sym_prefix # _func "_wrapper")) \
+  __pragma(section(".CRT$XCU",read)) \
+  __declspec(allocate(".CRT$XCU")) int (* _array ## _func)(void) = _func ## _wrapper;
+
+#define G_MSVC_DTOR(_func,_sym_prefix) \
+  static void _func(void); \
+  extern int (* _array ## _func)(void);              \
+  int _func ## _constructor(void) { atexit (_func); g_slist_find (NULL,  _array ## _func); return 0; } \
+   __pragma(comment(linker,"/include:" _sym_prefix # _func "_constructor")) \
+  __pragma(section(".CRT$XCU",read)) \
+  __declspec(allocate(".CRT$XCU")) 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/gtk/gtkapplication-dbus.c b/gtk/gtkapplication-dbus.c
index 3345a79573..b73d86046c 100644
--- a/gtk/gtkapplication-dbus.c
+++ b/gtk/gtkapplication-dbus.c
@@ -26,6 +26,8 @@
 #include "gtksettings.h"
 #include "gtkprivate.h"
 
+#include "gdk/gdkconstructor.h"
+
 G_DEFINE_TYPE (GtkApplicationImplDBus, gtk_application_impl_dbus, GTK_TYPE_APPLICATION_IMPL)
 
 #define DBUS_BUS_NAME               "org.freedesktop.DBus"