Store dwarf debug info in seperate files

It would be usefull if gcc builds can have their (dwarf) debug info in separate files,
just like the MSVC .pdb files.

The option -gsplit-dwarf looks promising,
Additionally, this wget distribution also has some way of separating it:
https://eternallybored.org/misc/wget/
This might be done how it's described here: http://stackoverflow.com/questions/16408893/gnu-ld-gdb-separate-debug-files-how-to-produce-the-debug-file-when-theres-too