amunits: syscallified icon unit

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28712 3ad0048d-3df7-0310-abae-a5850022a9f2
amunits: cleanup, removed the old amigasmartlinking define from icon

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28713 3ad0048d-3df7-0310-abae-a5850022a9f2