scanner: Put the -l library names after the .o

That is how gcc expects them.

From the gcc man page:
-llibrary
   Search the library named library when linking.

   It makes a difference where in the command you write this option; the linker
searches and processes libraries and object files in the order they are
specified.  Thus, foo.o -lz bar.o searches library z after file foo.o but
before bar.o.  If bar.o refers to functions in z, those functions may not be
loaded.

https://bugzilla.gnome.org/show_bug.cgi?id=664616