Build with newer Boost. From Fedora.

Index: gr-qtgui/lib/time_raster_sink_f_impl.cc
--- gr-qtgui/lib/time_raster_sink_f_impl.cc.orig
+++ gr-qtgui/lib/time_raster_sink_f_impl.cc
@@ -36,6 +36,8 @@
 namespace gr {
 namespace qtgui {
 
+using namespace boost::placeholders;
+
 time_raster_sink_f::sptr time_raster_sink_f::make(double samp_rate,
                                                   double rows,
                                                   double cols,
