[glade--]bug fix for label.cc

I found this when I created a non stock button with a stock image (which
creates a label for that button).  It was not handling mnemonics
properly in that case.  I tested it with a variety of possible labels
and buttons and it got them correct.

diff -u src/writers/label.cc ~/bugfixes/label.cc 
--- src/writers/label.cc        2002-12-19 16:54:41.000000000 -0500
+++ /root/bugfixes/label.cc     2002-12-19 16:54:21.000000000 -0500
@@ -36,6 +36,14 @@
 
 void Gtk_Label::ConstructionArgs(const Widget &w, CxxFile &f) const
 {  f.FunctionArg() <<
Configuration.Translatable(w.getProperty("label"));
+
+      std::string label=w.getProperty("label");
+      if ( GTKMM2 && 
+           w.getBoolProperty("use_underline") && 
+           ( label.find('_')!=std::string::npos ) )
+      {
+         f.FunctionArg() << "true";
+      }
 }
 
 bool Gtk_Label::NeedExplicitCtor(const Widget &w) const

Mark