include facility for .md files

[Aldy Hernandez <aldyh at redhat dot com>]

hi alan.

the md include system seems to only work for absolute path names.  i
added (include "altivec.md") to my rs6000.md but running gen* on it
gives me:

	altivec.md:13366: include file at  altivec.md not found

first, the error message is wrong, it should be:

	rs6000.md:13366: blah
	^^^^^^^^^

it can't open altivec.md because, at least for rs6000, the gen* programs
get fed an absolute path, ie:

./genattrtab /source/net/gcc/gcc/config/rs6000/rs6000.md > tmp-attrtab.c

init_md_reader() does not initialize base_dir when an absolute filename
is given.  consequently, process_include() does not have a relative
path, and tries to open altivec.md in the build directory.

to reproduce, just add a simple (include "foobar") to rs6000.md and try
to make gcc on powerpc-elf.

could you fix this?

thanks

-- 
Aldy Hernandez			E-mail: aldyh@redhat.com
Professional Gypsy
Red Hat, Inc.