[glibmm] Avoid use of NULL in C++

[Murray Cumming <murrayc src gnome org>]

commit e7d1d034a5327b05680009af16a061c967203627
Author: Murray Cumming <murrayc murrayc com>
Date:   Sun Mar 27 22:21:50 2011 +0200

    Avoid use of NULL in C++

 gio/src/fileoutputstream.hg |    2 +-
 glib/src/variant.hg         |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gio/src/fileoutputstream.hg b/gio/src/fileoutputstream.hg
index abfc53e..2c639e3 100644
--- a/gio/src/fileoutputstream.hg
+++ b/gio/src/fileoutputstream.hg
@@ -108,7 +108,7 @@ public:
    * For the synchronous version of this function, 
    * see query_info(). 
    * 
-   * If @a cancellable is not %NULL, then the operation can be cancelled by
+   * The operation can be cancelled by
    * triggering the cancellable object from another thread. If the operation
    * was cancelled, a Gio::Error with CANCELLED may be thrown
    * 
diff --git a/glib/src/variant.hg b/glib/src/variant.hg
index bccfda1..22c5d7a 100644
--- a/glib/src/variant.hg
+++ b/glib/src/variant.hg
@@ -176,7 +176,7 @@ template<class V_CastTo>
 V_CastTo VariantBase::cast_dynamic(const VariantBase& v)
 throw(std::bad_cast)
 {
-  if(v.gobj() == NULL)
+  if(!(v.gobj()))
   {
     return V_CastTo();
   }