[PATCH] add support for -imacros

[PATCH] add support for -imacros

Gcc has two ways to specify on the commandline files
to be read before processign normal files:

 "-include file" will include file in ordinary way.

 "-imacros file" will include file but do not generate any output

gcc will include files specified with -imacros before files specified
with -include.

This adds some very basic support for -imacros, just duplicating the
code used for -include.

To obtain the real functionality we would have to build a list of
filenames specified, and process all files specifed with -imacros before
files specified with -include.

In -mm a patch is now included that uses -imacros, so applying following
patch will let us stay compatible with kernel source.  The last bit
deletes two references from lib.h that are there for no good reason.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>