fbc-debug: Add debug info for included files

[jayrm]

This update from SARG and St_W adds filename debug information for included files.

• This patch adds debug file name information for included files to allow the debugger to determine the filename origin of module-level statements, which may be in both the main file and included files
• Previously, only the top level file name was emitted to the debug information

Original discussion at Bug fix for debugging lines inside include files

Results are comparable on 32-bit and 64-bit and gdb appears to generate a meaningful backtrace.