Re: don't force CXX and F77 to be configured in

[Ralf Wildenhues]

Hi Alexandre, others,

* Alexandre Oliva wrote on Sun, Apr 17, 2005 at 10:28:30PM CEST:
> Currently, at least in the 1.5 branch, a configure.ac as simple as:
*snip*
> causes libtool to be configured for CXX and F77, in addition to the
> implicitly requested CC tag.
> 
> That's caused by an undesirable interaction between _LT_AC_TAGCONFIG
> and the code that detects whether AC_PROG_{CXX,F77} were used:
> _LT_AC_TAGCONFIG expands unconditionally macros that AC_REQUIRE
> AC_PROG_CXX and AC_PROG_F77, such that the test whether they are
> provided always results positive.
> 
> This patch avoids expanding the AC_REQUIREing macros if they haven't
> been explicitly brought in before, using the same logic as the
> existing test, thereby fixing the problem.  Ok to install?

I have tested this some more (and also looked at past discussions).
This incompatibility:

> Incidentally, I noticed that, even after the fix, adding AC_PROG_CXX
> or AC_PROG_F77 after AC_PROG_LIBTOOL doesn't trigger the autoconf
> AC_BEFORE error I expected; it instead now causes a configure-time
> error because the CXX and F77 sections of _LT_AC_TAGCONFIG are
> missing.  I wish we could do better than this, but I couldn't quite
> figure out how.

is the main reason I think it should _not_ be added to branch-1-5,
but to keep pushing for 2.0.  The major breakage it will cause is just
not worth the savings, if all we need is to wait a tad longer.

> > * Alexandre Oliva wrote on Sun, Apr 24, 2005 at 12:42:42AM CEST:
> >> 
> >> Erhm...  If this is going out soon, could we perhaps get the patch I
> >> posted for libtool.m4 in, to avoid configuring CXX and F77 in every
> >> single libtool script, part of packages that only care about C?

Sorry.

Regards,
Ralf