With the reduction of search depth, "prereq abiword" takes about 3 minutes
on my PC. (Obviously, this can still be improved.)
- gobble.c (gobble_buf): if pkg->id->value is NULL, just it as such
- prereq.c (push): abort if trying to consider a package already considered
or installed
- prereq.c (conflicts): before being satisfied with using an installed
package, make sure it really satisfies the requirement
- prereq.c (conflicts): abort if an installed package conflicts
- prereq.c (conflicts): added some debugging output (temporary)
- prereq.c (conflicts): cut the search if we can't do better than a
previous match
