re PR preprocessor/14103 (ICEs on "gcc -E -imacros foo.h baz.c")

re PR preprocessor/14103 (ICEs on "gcc -E -imacros foo.h baz.c")

	* cpphash.h (struct cpp_buffer):  Restore return_at_eof field.  This
	partly reverts my 2003-10-01 change, because we're back to logically
	including <command line> inside the main line.
	* cpplex.c (_cpp_get_fresh_line):  Check return_at_eof field.
	* cppmacro.c (cpp_scan_nooutput):  Set return_at_eof of current buffer.
	Fixes PR preprocessor/14103.

	* cppfiles.c (_cpp_stack_include):  When appropriate decrement
	line_table's highest_location, fixing LAST_SOURCE_LINE_LOCATION.
	(cpp_push_include):  Don't need to increment pfile's line field.
	* line-map.h (LAST_SOURCE_LINE_LOCATION):  Only decrement by 1.

	* c-ppoutput.c (print struct):  New first_time field.
	(init_pp_output):  Set print.first_time.
	(pp_file_change):  Use print.first_time, rather than MAIN_FILE_P,
	which is set also for (say) <command line>.  Clear print.first_time.

	* cppfiles.c (struct _cpp_file):  Comment and type for pch field
	does not match the code, so fix both.
	(should_stack_file):  Inline include_pch_p function.
	(include_pch_p):  Remove pointless function.

	* cpphash.h (struct cpp_buffer):  Remove unused search_cached field.

From-SVN: r78049