This adds native support in WLINK for generating DOS extended programs t...

This adds native support in WLINK for generating DOS extended programs that use [PMODE/WI](http://www.sid6581.net/pmodew/) and [WDOSX](http://tippach.business.t-online.de/wdosx/).

PMODE/WI is the tiny version of the PMODE/W DOS extender, that thanks to removing some capabilities, further reduces its overhead to about 8 KB.

WDOSX for Wuschel's DOS eXtender, is another DOS extender supporting various development environments, in particular Watcom/OpenWatcom.

This is done by updating WLINK.LNK that is generated throught bld/wl/lnk/specs.sp.