Improve handling of import code from library
On Windows:
- Items starting with -l are ignored
- Everything else is treated as an ASCII library file
On other platforms:
- Items starting with -l are treated as shared libraries
- Items containing a dot are treated as normal files and linked
- Other items are ignored
This allows one to use for example:
import code from library "mylib_library"
import code from library "-lmylib"(where Clean System Files\mylib_library refers to mylib.dll or so). The first entry is used on Windows; the second on non-Windows.