Hi Rob,

this one turned out to be harder than expected.

First of all, I have to correct myself. While I did a ./configure --disable-static --enable-shared for gmp-4.2.1, I didn't check on the results, which was neglegance on my part - there were none. There is a problem with libgmp's configure script, which prevents shared libraries from being built, and silently falls back to static. Duh.

After upgrading libtool (which didn't resolve anything), I found the following patch here, which immediately solves the problem:

--- configure.old       2006-07-19 11:01:44.000000000 +0200
+++ configure   2006-07-19 10:49:59.000000000 +0200
@@ -12547,7 +12547,7 @@
       ;;
 
     darwin* | rhapsody*)
-    if test "$GXX" = yes ; then
+    if test "$GCC" = yes ; then
       archive_cmds_need_lc=no
       case "$host_os" in
       rhapsody* | darwin1.[012])
[download]

Now that the shared library has been built, everything works fine for Math::GMP without further intervention, just as you expected.

dailuaine:~/Documents/Develop/Math-GMP-2.04 pete$ perl Makefile.PL
Writing Makefile for Math::GMP
dailuaine:~/Documents/Develop/Math-GMP-2.04 pete$ make 
gcc -c   -fno-common -DPERL_DARWIN -no-cpp-precomp -fno-strict-aliasin
+g -pipe -Wdeclaration-after-statement -I/usr/local/include -I/opt/loc
+al/include -O3   -DVERSION=\"2.04\" -DXS_VERSION=\"2.04\"  "-I/usr/lo
+cal/lib/perl5/5.8.8/darwin-2level/CORE"   GMP.c
Running Mkbootstrap for Math::GMP ()
chmod 644 GMP.bs
rm -f blib/arch/auto/Math/GMP/GMP.bundle
LD_RUN_PATH="/usr/local/lib" env MACOSX_DEPLOYMENT_TARGET=10.3 cc  -bu
+ndle -undefined dynamic_lookup -L/usr/local/lib -L/opt/local/lib GMP.
+o  -o blib/arch/auto/Math/GMP/GMP.bundle         \
   -lgmp        \
  
chmod 755 blib/arch/auto/Math/GMP/GMP.bundle
cp GMP.bs blib/arch/auto/Math/GMP/GMP.bs
chmod 644 blib/arch/auto/Math/GMP/GMP.bs
Manifying blib/man3/Math::GMP.3
dailuaine:~/Documents/Develop/Math-GMP-2.04 pete$ make test 
PERL_DL_NONLAZY=1 /usr/local/bin/perl "-MExtUtils::Command::MM" "-e" "
+test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
t/gmppm....ok                                                         
+       
All tests successful.
Files=1, Tests=350,  1 wallclock secs ( 0.21 cusr +  0.04 csys =  0.25
+ CPU)
[download]

Thanks again for your help. It seems that the problem is on the libgmp side, so I'll send the problem description and the workaround to the developers.

Best regards,

  Peter.