build failure introduced by r14955 with autotools-based build

[su_v]

Latest trunk r14955 fails to compile with autotools-based build:

  CXX extension/param/parameter.o
In file included from /Volumes/magenta/mp-trunk/x11/include/glibmm-2.4/glibmm.h:89,
                 from /Volumes/magenta/mp-trunk/x11/include/gtkmm-2.4/gtkmm/table.h:7,
                 from ./ui/widget/color-notebook.h:25,
                 from extension/param/parameter.cpp:25:
/Volumes/magenta/mp-trunk/x11/include/glibmm-2.4/glibmm/threads.h:209: error: field ‘gobject_’ has incomplete type
/Volumes/magenta/mp-trunk/x11/include/glibmm-2.4/glibmm/threads.h: In member function ‘GThread* Glib::Threads::Thread::gobj()’:
/Volumes/magenta/mp-trunk/x11/include/glibmm-2.4/glibmm/threads.h:205: error: ‘gobject_’ was not declared in this scope
/Volumes/magenta/mp-trunk/x11/include/glibmm-2.4/glibmm/threads.h: In member function ‘const GThread* Glib::Threads::Thread::gobj() const’:
/Volumes/magenta/mp-trunk/x11/include/glibmm-2.4/glibmm/threads.h:206: error: ‘gobject_’ was not declared in this scope
make[3]: *** [extension/param/parameter.o] Error 1

A cmake-based build on the other hand succeeds (same build environment otherwise, all tests done on OS X 10.7.5), as does one with btool on Windows (as confirmed on irc by the author of r14955).

Changing the order of the includes (see attached diff) allows to compile r14955 successfully with autotools-based build. Please review the proposed diff and apply if ok.

[Patrick Storz (ede123)]

Committed as part of revision 14978
http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/14978