[glibmm] Add _CUSTOM_CTOR_CAST macro for _CLASS_OPAQUE_COPYABLE.

[Krzesimir Nowak <krnowak src gnome org>]

commit a79200da81698a3ea51b911737f2525393a30079
Author: Krzesimir Nowak <qdlacz gmail com>
Date:   Sun Jul 22 19:47:21 2012 +0200

    Add _CUSTOM_CTOR_CAST macro for _CLASS_OPAQUE_COPYABLE.
    
    * tools/m4/class_opaque_copyable.m4: New macro.

 ChangeLog                         |    6 ++++++
 tools/m4/class_opaque_copyable.m4 |    9 +++++++++
 2 files changed, 15 insertions(+), 0 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 4f8f4b6..420883b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2012-07-28  Krzesimir Nowak  <qdlacz gmail com>
+
+	Add _CUSTOM_CTOR_CAST macro for _CLASS_OPAQUE_COPYABLE.
+
+	* tools/m4/class_opaque_copyable.m4: New macro.
+
 2012-07-26  Kjell Ahlstedt  <kjell ahlstedt bredband net>
 
 	Glib::Threads:[Rec]Mutex: Add wrap() functions.
diff --git a/tools/m4/class_opaque_copyable.m4 b/tools/m4/class_opaque_copyable.m4
index 9223e88..81be7b5 100644
--- a/tools/m4/class_opaque_copyable.m4
+++ b/tools/m4/class_opaque_copyable.m4
@@ -21,6 +21,13 @@ define(`__BOOL_CUSTOM_DEFAULT_CTOR__',`$1')
 _POP()
 ')
 
+define(`_CUSTOM_CTOR_CAST',`dnl
+_PUSH()
+dnl Define this macro to be tested for later.
+define(`__BOOL_CUSTOM_CTOR_CAST__',`$1')
+_POP()
+')
+
 _POP()
 _SECTION(SECTION_CLASS2)
 ') dnl End of _CLASS_OPAQUE_COPYABLE.
@@ -91,6 +98,7 @@ __CPPNAME__::__CPPNAME__`'(const __CPPNAME__& src)
   gobject_ ((src.gobject_) ? __OPAQUE_FUNC_COPY`'(src.gobject_) : 0)
 {}
 
+ifdef(`__BOOL_CUSTOM_CTOR_CAST__',,`dnl else
 __CPPNAME__::__CPPNAME__`'(__CNAME__* castitem, bool make_a_copy /* = false */)
 {
   if(!make_a_copy)
@@ -108,6 +116,7 @@ __CPPNAME__::__CPPNAME__`'(__CNAME__* castitem, bool make_a_copy /* = false */)
       gobject_ = 0;
   }
 }
+')
 
 ifelse(__OPAQUE_FUNC_COPY,NONE,`dnl
 ',`dnl else