clients: Make libtoytoolkit a libtool library
clients: Make libtoytoolkit a libtool library

This way libtool will remember the libtoytoolkit LIBADD libraries.
We can drop the toolkit_libs hack and just link to libtoytoolkit.la and
libtool will add the dependencies.

Fantu/compositor-spice,eyolfson/weston,eyolfson/weston,sir-murray/weston,xorgy/weston,giucam/weston,sir-murray/weston,Tarnyko/weston-xdg_surface_present,xorgy/weston,jonnylamb/weston,udoprog/weston,mchalupa/weston,Gnurou/weston,giucam/weston,Tarnyko/weston-xdg_surface_present,jonnylamb/weston,Gnurou/weston,krezovic/weston,udoprog/weston,Fantu/compositor-spice,krezovic/weston,kwm81/weston,mchalupa/weston,kwm81/weston,Fantu/compositor-spice