Newbie: cannot use gtk_button_set_label

[Neoklis Kyriazis <neoklis users sourceforge net>]

Hi all,

In my app I would like to change a GtkButton's label on cliked event.
I have tried to use 'gtk_button_set_label' but I get the following:

warning: implicit declaration of function `gtk_button_set_label'

and compilation fails. I have both gtk+ 1.2 and gtk+ 2.0 installed since
they are both needed and autogen seems to have setup the makefiles for
gtk+ 1.2. I tried changing the makefiles to 2.0 but I get 

/usr/include/gtk-2.0/gdk/gdktypes.h:33: pango/pango.h: No such file or
directory
/usr/include/gtk-2.0/gdk/gdktypes.h:51: gdkconfig.h: No such file or
directory
/usr/include/gtk-2.0/gtk/gtkwidget.h:36: atk/atkobject.h: No such file
or directory

and other similar errors. Any clues?

My thanks in advance.

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