[glibmm] Use nullptr intead of 0 in some generated code.

[Murray Cumming <murrayc src gnome org>]

commit 8f27f3b6308a351cd20c756a198eb7616c9ac9e6
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Nov 19 11:57:32 2015 +0100

    Use nullptr intead of 0 in some generated code.

 glib/src/signalproxy.h.m4 |    4 ++--
 tools/pm/Output.pm        |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/glib/src/signalproxy.h.m4 b/glib/src/signalproxy.h.m4
index af02e7f..8752624 100644
--- a/glib/src/signalproxy.h.m4
+++ b/glib/src/signalproxy.h.m4
@@ -60,8 +60,8 @@ public:
   {
     const auto pConnectionNode = static_cast<SignalProxyConnectionNode*>(data);
 
-    // Return 0 if the connection is blocked.
-    return (!pConnectionNode->slot_.blocked()) ? &pConnectionNode->slot_ : 0;
+    // Return nullptr if the connection is blocked.
+    return (!pConnectionNode->slot_.blocked()) ? &pConnectionNode->slot_ : nullptr;
   }
 #endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
diff --git a/tools/pm/Output.pm b/tools/pm/Output.pm
index 587d06b..71c2ceb 100644
--- a/tools/pm/Output.pm
+++ b/tools/pm/Output.pm
@@ -1208,7 +1208,7 @@ sub convert_args_cpp_to_c($$$$$)
       my $initialization = "";
       if($cOutputParamType =~ /\*$/)
       {
-        $initialization = " = 0"; 
+        $initialization = " = nullptr"; 
       }
       else
       {