cups-filters: Fix symlinks to executables

[dmik]

Turns out that cups makefiles creates a lot of symlinks to executables (e.g. /@unixroot/usr/bin/driverless pointing to /@unixroot/usr/lib/cpus/driver/driverless) but they lack the .exe extension which makes these symlinks completely broken (i.e. the proper file for the above case is /@unixroot/usr/lib/cpus/driver/driverless.exe).

Please note that it's enough to only fix the link's target — the link itself doesn't need an .exe extension in order to work from under sh. It's even desirable that the link itself doesn't have an .exe extension — this will avoid recognising it as an executable by native OS/2 tools like CMD.EXE that don't support kLIBC symlinks so they will fail to execute it anyway.

So, in the above case the fix is to make /@unixroot/usr/bin/driverless point to /@unixroot/usr/lib/cpus/driver/driverless.exe, but no need to add .exe to the symlink itself.