> I've compiled without any errors 3.23.20 on OS X Darwin
> 6.6 using gcc 
> 3.1. 

Can you try either to use gcc 2.95 or gcc 3.2 ? There were 
problems reported with 3.1 and earlier releases

> The only problem so far is that I'm getting segmentation 
faults when 
> running httrack. 

Did you try using gdb to trace where the problem occurs?
To enable symbol and debug:
CFLAGS="-g -O0" ./configure && make && make install

And then, using gdb:

$ gdb httrack
(gdb) set args www.foo.com -O /tmp/test
(gdb) run
..
<crash appears>
(gdb) where
<useful info>..
(gdb) info local
<useful info>..
(gdb) info line
<useful info>..

>Some sites gather OK and httrack exits without any 
>errors, but on most sites it doesn't.

Can you give an example which "always" crash if this is 
possible ?
> Any idea what might be causing this? 

Absolutely not :(
httrack is tested on several platforms (i386, alpha 64-bit, 
sparc 32/64) but NOT on OSX. I asked several times Apple if 
they got an online access to an OSX box to test for 
developpers like me (I do not have, unfortunately, neither 
the money nor the space to have another server) as several 
vendors like HP or IBM do, but they do not want to provide 
such access :(

>A propos, has anyone
> got a OS X 
> binary that runs OK?
Several folks tried to compile it, with success ; but there 
is a lack of feedback