Contrary to popular believe the VMT for a generic needs to be at least generated so that check for inherited methods can be done correctly. This does however not mean that the VMT is written to the object file which is handled at a completely different place. Fixes Mantis #26193.

pdecl.pas, types_dec:
  * invoke the VMT builder for generic classes as well

+ added test

git-svn-id: trunk@27869 -