`\tl_new:N \l_tmpc_tl` may cause clashes

[fpantigny]

The code uses \tl_new:N \l_tmpc_tl and \tl_new:N \l_tmpd_tl.
Other packages may have the same idea (creation of new draft token lists after the existing ones \l_tmpa_tl and \l_tmpb_tl), I think it would be better to use \tl_clear_new:N instead of \tl_new:N in order to avoid clashes.

[loopspace]

Well spotted, thanks.

This package was one of my first forays into L3 coding so suffers from many bad practices that I've since learnt not to do. In more recent code I've been using package-specific temporary variables, I think that's what I should do here.