* msdos startup code for tiny and small memory models moved to a shared nasm include file to avoid code duplication

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24808 3ad0048d-3df7-0310-abae-a5850022a9f2
* prt0 startup code file for small model renamed to prt0s

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24809 3ad0048d-3df7-0310-abae-a5850022a9f2
* makefiles updated after the msdos loader changes

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24810 3ad0048d-3df7-0310-abae-a5850022a9f2