Currently, dbghelp returns the source file either:
- in DOS format when native module option isn't enabled
- as stored in debug info format otherwise

This used to work for PE modules inside ELF shared libraries but is broken
since evolution to REAL modules. This generates several issues:
- winedbg does not always set the native module option when calling dbghelp
  for source file related functions, leading to heterogenous output to user
- some dbghelp function rely on matching source paths, hence leading to
  errors in winedbg when mixing the two formats for the same source file.

Introduce a new Wine only dbghelp option to return the source paths as they
are stored inside debug information format, and activate it unconditionaly
inside winedbg.

This fixes some failure cases of command 'break <NN>' in winedbg.
Signed-off-by: Eric Pouech <epouech@codeweavers.com>