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

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

On Wed, May 02, 2001 at 07:41:23PM -0700, Benjamin Kosnik wrote:
> 
> Then perhaps AC_PROG_CXXCPP needs to be done so that it's 
> $(blddir)/../../gcc/xgcc -B./ -E
> 
> or whatever.

It tries that.  But it tries it on a file containing "#include <stdlib.h>"
which fails because stdlib.h cannot be found for the cross-compiler.
So autoconf concludes that "xgcc -Bprefix -B. -E" is the wrong thing to do.

I think it tries one more combination of compiler+"-E" before giving up
and falling back on /lib/cpp, but I don't recall.


I suppose our test in acinclude.m4 could pre-set CXXCPP /before/ calling
AC_EGREP_CPP, under the assumption that the library is always being built
during a compiler build, thus a compiler is always there.  Come to think
of it, we should probably be doing that anyhow for all such variables,
rather than allowing autoconf to look for them at all.


Phil

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