re PR fortran/33502 (gfortran with .F suffix and -g3 option chokes on preprocessor...

re PR fortran/33502 (gfortran with .F suffix and -g3 option chokes on preprocessor syntax)

	PR fortran/33502
	* scanner.c (gfc_advance_line): Call debug_hooks->start_source_file
	and debug_hooks->end_source_file when entering and exiting
	included files.
	(gfc_define_undef_line): New function.
	(load_file): Ignore #define and #undef preprocessor lines
	while reading source files.
	* parse.c (next_statement): Handle #define and #undef
	preprocessor lines.
	(gfc_parse_file): Call debug_hooks->start_source_file and
	debug_hooks->end_source_file for the main source file if
	requested by the debug format.
	* gfortran.h (gfc_define_undef_line): Add prototype.

From-SVN: r128671