about building libobjc_gc

[Nicola Pero <nicola at brainstorm dot co dot uk>]

libobjc is currently built with garbage collecting only if an external
boehm-gc library is provided.

There was a discussion long ago

http://gcc.gnu.org/ml/gcc/2001-01/msg01019.html

about using the boehm-gc library provided with GCC.  (I haven't
investigated the issue myself, and I'm not sure on the question of
ALL_INTERNAL_POINTERS, but I can investigate).

There has been recently some interest in garbage collector support for
Objective-C.  I've been sent a very simple patch to build Objective-C
using the GCC supplied boehm-gc, and to always build boehm-gc when
Objective-C is enabled, and always build libobjc_gc (as well as libobjc)
when Objective-C is enabled.

What is the general feeling about such patches ?

How portable is boehm-gc ?  More or less than libobjc ? Can we build
libobjc_gc by default on some platforms and not build it on more
'difficult' platforms ?  Most people use libobjc for 'real things', and
only use libobjc_gc as a toy, so while I think it would be nice that GCC
which are shipped with GNU/Linux distributions etc include libobjc_gc so
that people can toy with it, maybe we shouldn't built such a thing on all
platforms if that would mean objc support is available on less platforms.  
<Maybe we should just recommend to build GCC with --enable-objc-gc ?>

I assume we all agree that it would be indeed nice that the GCC supplied
boehm-gc is used when libobjc is built with GC enabled, and that a patch
implementing that would be ok (I think adding a proper -I is enough,
assuming that the boehm-gc shipped with GCC is not too much Java-biased
and works well with ObjC).

Comments welcome.