glib: SYNCEVO_GLIB_CALL_SYNC() must use GRunWhile()

Like everything else that waits for a certain event on the main loop,
SYNCEVO_GLIB_CALL_SYNC() should also better use GRunWhile(). This is
necessary to be usable in threads.

src/syncevo/GLibSupport.h

@@ -42,6 +42,7 @@ typedef void *GMainLoop;
 #include <boost/type_traits/remove_pointer.hpp>
 #include <boost/type_traits/function_traits.hpp>
 #include <boost/utility/value_init.hpp>
+#include <boost/lambda/lambda.hpp>
 
 #include <iterator>
 #include <memory>
@@ -1033,9 +1034,7 @@ template<> class GAsyncReadyDoneCXX<void>
         SYNCEVO_GLIB_CALL_ASYNC(_prepare, \
                                 GAsyncReadyDoneCXX<boost::function<typeof(_prepare ## _finish)>::result_type>::createCB(_res, _gerror, done), \
                                 _args); \
-        while (!done) { \
-            g_main_context_iteration(NULL, true); \
-        } \
+        GRunWhile(! boost::lambda::var(done)); \
     } while (false); \