Re: Remove dependency on C++ compiler

On Sun, 7 May 2006, Bram Matthys (Syzop) wrote:

>> So this is code originating from libtool? libtool is GPL licensed and we
>> cannot easily just merge in code from them into c-ares.
>
> I think you'll have to ask Paolo Bonzini to be sure. Or instead use your own
> judgement.
>
> Let me know if it cannot be used. Because TRE (another lib) used it, and TRE
> recently went from GPL to LGPL, so if he cannot use it anymore, he probably
> wants to know as well (even though MIT!=LGPL I suppose).

Ok, I'm not a lawyer and I don't intend this to become a license argument, but
this is my understanding of these things:

The GPL states that if we include code in our project that is licensed as GPL
we need to offer our full package as GPL. And I don't want to do that.
Therefore we avoid including anything that is GPL licensed.

We are perfectly allowed to include it if we just make that license
"sacrifise". The same goes for projects using LGPL.

> If I'm not mistaken, this AC_LIBTOOL_TAGS is a general thing, which can be
> called in a certain way so to enable for example both C and C++, or only
> fortran, only xyz, etc. It allows you to choose...

> So it's not designed to specificly remove everything except C. I wouldn't be
> surprised if for (y)our purpose it can be made shorter.
> I'm simply using this one, because I know from past experience it works ok.

Ok, I'm not an autoconf/libtool expert, but it seems to me that by extracting
what your fix actually does and only doing that works just the same and with a
lot less code. Does this work for you as well?

--- acinclude.m4 9 Jan 2006 08:31:48 -0000 1.29
+++ acinclude.m4 7 May 2006 21:58:46 -0000
@@ -826,3 +826,12 @@
  fi
  ])

+# Prevent libtool for checking how to run C++ compiler and check for other
+# tools we don't want to use.
+#
+# ARES_CLEAR_LIBTOOL_TAGS
+# ---------------
+# tags to enable
+AC_DEFUN([ARES_CLEAR_LIBTOOL_TAGS],
+ [m4_define([_LT_AC_TAGCONFIG])]
+)
Index: configure.ac
===================================================================
RCS file: /cvsroot/curl/curl/ares/configure.ac,v
retrieving revision 1.43
diff -u -r1.43 configure.ac
--- configure.ac 3 May 2006 22:39:49 -0000 1.43
+++ configure.ac 7 May 2006 21:58:46 -0000
@@ -66,6 +66,7 @@
  )

  dnl libtool setup
+ARES_CLEAR_LIBTOOL_TAGS
  AC_PROG_LIBTOOL

  dnl Checks for header files.

-- 
   c-ares -- my preferred DNS asynch resolver library