Re: aclocal-1.8/m4_include behaving oddly

[Andreas Schwab]

Phil Edwards <address@hidden> writes:

> One of the GCC runtime libraries (libstdc++-v3) has for years contained
> the following lines in acinclude.m4:
>
>     m4_include([../libtool.m4])
>     dnl The lines below arrange for aclocal not to bring an installed
>     dnl libtool.m4 into aclocal.m4, while still arranging for automake to
>     dnl add a definition of LIBTOOL to Makefile.in.
>     ifelse(,,,[AC_SUBST(LIBTOOL)
>     AC_DEFUN([AM_PROG_LIBTOOL])
>     AC_DEFUN([AC_LIBTOOL_DLOPEN])
>     AC_DEFUN([AC_PROG_LD])
>     ])
>
> I've been content to ignore them, since I don't understand libtool.
> But now we're trying to move to the latest released tools, and aclocal
> 1.8 flags errors dealing with that block:
>
>     aclocal: macro `_AC_PROG_LIBTOOL' required but not defined
>     aclocal: macro `_AC_LIBTOOL_CXX' required but not defined
>     aclocal: macro `_AC_LIBTOOL_GCJ' required but not defined

Which means that you don't have libtool.m4 in $datadir/aclocal.  

> On the advice of a colleague, I tried adding "-I .." to the command line.
> This worked.

Previous versions of aclocal also required this.  If you run aclocal
1.7.x with --verbose you will see that it never looks at ../libtool.m4
unless you pass "-I ..".

> Unless I'm missing some important piece of philosophy, this is also very very
> poor behavior.  We've specifically *told* autowhatever to get a file from
> ".."  and it's definitely doing something with that file (moving it away
> leads to file-not-found errors).  But the definitions inside are somehow
> being ignored, unless we futz with redundant command line options.

aclocal has never looked at (m4_|s)include while collecting files for
scanning.

> We have tried very hard to avoid requiring developers to pass arguments
> to the various autotools, largely because there's no way to help them do
> so automatically.

What's wrong with "ACLOCAL_AMFLAGS = -I .." in Makefile.am?

> And just recently I've been factoring out pieces of our large
> acinclude.m4 into various smaller .m4 files; if the behavior of
> m4_include is suddenly different, we'll have to rethink all that.

There was no change in behaviour.  It only worked before because you
had the libtool macros installed in $datadir/aclocal.  Presumably you
are using a different prefix for your automake 1.8 installation, so
that $datadir/aclocal is empty or does not exist.

Andreas.

-- 
Andreas Schwab, SuSE Labs, address@hidden
SuSE Linux AG, Maxfeldstraße 5, 90409 Nürnberg, Germany
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