libstdc++, autoconf, and /lib/cpp (was Fw: Re: GCC 3.0 Status Report)

[Phil Edwards <pedwards at disaster dot jaj dot com>]

I'm changing the subject line because otherwise I get the most bizzare
conversations all threaded under "3.0 Status Report" due to the followups
from Mark's announcements.


On Wed, May 02, 2001 at 11:51:18AM -0700, Benjamin Kosnik wrote:
> 
> note this is libstdc++/2255.

Yep.  Definitely read over the audit-trail conversation there.  This is
sort of an autoconf bug, but might be some user error also:

There's also a bit on the GCC configuration instructions page which adds

#   Some options which only apply to building cross compilers:
#
#   --with-headers=dir -- Specifies a directory which has target include
#   files. This options is required when building a cross compiler, if
#   ${prefix}/${target}/sys-include doesn't pre-exist.

I don't know whether libstdc++/2255 specified that option or not.  The note
from Toshi didn't, but he may just not have repeated the entire configure
command in his email.

Anyhow, I made an empty foo/sh-elf/sys-include directory, touch'd an
empty stdlib.h, and configured with --prefix=foo --target=sh-elf, and
the configure went just fine[*].  The half-dozen calls to v3's configure
worried me until I realized that it really does have all those multilibs.

[*]  Actually, it failed.  Then I renamed sys-include to include, and
it worked.  Dunno about that.


> I suppose we could just use AC_TRY_COMPILE here.

Wouldn't that be tricker than calling just the preprocessor?  If the system
headers aren't being found during configure, then things are only going
to get worse.

I realized that I'm repeating the arguments in 2255.  :-)


-- 
pedwards at disaster dot jaj dot com  |  pme at sources dot redhat dot com
devphil at several other less interesting addresses in various dot domains
The gods do not protect fools.  Fools are protected by more capable fools.