Re: PATCH to represent column numbers using source_location

[Per Bothner <per at bothner dot com>]

There are of course a number of solutions.  I'm leaning towards (2),
as the simplest and safest.

Allow line-map.h to be #included even if line-map.o isn't linked:
(1) Don't inline linemap_position_for_column.
    It is (currently) only used once in a possibly preformance-critical
    location (_cpp_lex_direct), so inlining is probably desirable.
(2) Use a macro for inline linemap_position_for_column.
    Somewhat ugly.
(3) Inline linemap_line_start as well.
    This is used more often, and is bigger, so inlining may be nonoptimal.

Link in line-map.o wih gengtype etc:
(4) link line-map.o with gengtype (and anything else that inlcudes rtl.h)

Don't include line-map.h in gengtype.c:
(5) Don't #include line-map.h in rtl.h
    Problem: location_t needs to be defined.
(6) Don't include line-map.h in input.h.
    Problem: We will need the source_location typedef once we replace
    struct location_s by source_location.
    Possible fix: Move the source_location typedef to coretypes.h.
--
	--Per Bothner
per@bothner.com   http://per.bothner.com/