Many thanks for your continued help.

Running with the -xs flag I still get the same result during tests:

t/weak..........skipped
        all skipped: weaken requires XS version
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I looked at the code for Module::Install:Can, and the guts involve $Config::Config{cc} so I did check:

$ perl -MConfig -e 'print $Config::Config{cc}'
gcc
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Which I guess isn't surprising since I haven't had troubles building other xs-based modules. The check in weak.t looks at @Scalar::Util::EXPORT_FAIL, and it does look like the code being executed is in: perl5.8.7/lib/5.8.7/Scalar/Util.pm.

So after that I'm still not quite sure what's going on. In the make output I see:

gcc -c   -D_ALL_SOURCE -D_ANSI_C_SOURCE -D_POSIX_SOURCE -DUSE_NATIVE_D
+LOPEN -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGE_FILES 
+-O   -DVERSION=\"1.18\" -DXS_VERSION=\"1.18\"  "-I/db2blast/Paul/perl
+5.8.7/lib/5.8.7/aix/CORE"  -DPERL_EXT Util.c
Running Mkbootstrap for List::Util ()
chmod 644 Util.bs
rm -f blib/arch/auto/List/Util/Util.so
gcc  -Wl,-bhalt:4 -Wl,-bexpall -Wl,-G -Wl,-bnoentry -lc -L/usr/local/l
+ib Util.o  -o blib/arch/auto/List/Util/Util.so    \
        \

chmod 755 blib/arch/auto/List/Util/Util.so
cp Util.bs blib/arch/auto/List/Util/Util.bs
chmod 644 blib/arch/auto/List/Util/Util.bs
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and during make install I get:

Installing /db2blast/Paul/perl5.8.7/lib/5.8.7/aix/auto/List/Util/Util.
+so
Files found in blib/arch: installing files in blib/lib into architectu
+re dependent library tree
Writing /db2blast/Paul/perl5.8.7/lib/5.8.7/aix/auto/List/Util/.packlis
+t
Appending installation info to /db2blast/Paul/perl5.8.7/lib/5.8.7/aix/
+perllocal.pod
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Which I had thought indicates successful building of the xs code. I also tried uninstalling with:

cpan> o conf make_install_arg UNINST=1
    make_install_arg   [UNINST=1]

cpan> force install Scalar::Util
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Which led to the same result. Might you have any other ideas of what I could try or where I could look?

From the dialogues that you reported, it looks like the xs version of the package got built and installed OK. I'm not sure why the t/weak.t test still reported that the xs version was needed - perhaps a make distclean is needed before rerunning perl Makefile.PL. In any case, does this fix the original problem with the Graph module?

Hi again,

Unfortunately it doesn't -- the check you initially pointed out in Graph/Makefile.PL still fails:

# Some Debian distributions have a broken List::Util (see rt.cpan.org 
+#9568)
eval 'require Scalar::Util; import Scalar::Util qw(weaken)';
if ($@) {
    die <<__EOF__;
$@
You do not have Scalar::Util::weaken, cannot continue, aborting.
__EOF__
}
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It doesn't appear I have an "extra" version of Scalar::Util anywhere, either:

./lib/5.8.7/aix/auto/List/Util/Util.so
./lib/5.8.7/aix/auto/List/Util/Util.bs
./lib/5.8.7/aix/List/Util.pm
./lib/5.8.7/aix/Scalar/Util.pm
./lib/5.8.7/CGI/Util.pm
./lib/5.8.7/Hash/Util.pm
./lib/site_perl/5.8.7/HTTP/Headers/Util.pm
./lib/site_perl/5.8.7/Data/Stag/Util.pm
./lib/site_perl/5.8.7/Bio/Graphics/Util.pm
./lib/site_perl/5.8.7/Crypt/DSA/Util.pm
./lib/site_perl/5.8.7/Crypt/OpenPGP/Util.pm
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It appears that the xs is getting installed okay, but is not being exported and so weaken() appears in @EXPORT_FAIL. I'm willing to put in more time trying to debug this, but I don't even have a clue where to start on seeing why the export fails. Any pointers on where to start looking?