[cc1] Fix segfault in mktype()
[cc1] Fix segfault in mktype()

The patch 6ab66ac added a check about the last parameter
in the parameter list, but this check was incorrect when nelem == 0,
because we were accesing further or the borders of the array.

k0gaMSX/scc,k0gaMSX/scc,k0gaMSX/scc