Check compilation of libraries

[daar]

Check if pmake is capable of building libraries. Add an example to the repository.

[daar]

pmake --quickstart fails with

... generating build information
... parse subdirectory calls
An unhandled exception occurred at $00414983:
EStringListError: List index (-1) out of bounds
  $00414983
  $0042A877
  $00401D00

[daar]

On compiling the dynamic library is created, but without filename extension.

[daar]

Example added in commit f222dcc

[daar]

By using the $(DLL) macro the file extension issue is fixed.

add_executable('subs', 'subs$(DLL)', 'subs.pp', []);