32RTM and BRUN45 incompatibilities fixed by Michael.
ZIP drive serial numbers now work: bug fix by Lucho.
Small clean-ups and optimisations by Lucho & Arkady.
git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/branches/UNSTABLE@1023 6ac86273-5f31-0410-b378-82cca8765d1b