Perl5 Interface Problems...

When compiling the perl5 support from perl 5.6 I get the following...

[root(at)thinkpad-770x perl5]# perl Makefile.PL
Checking if your kit is complete...
Looks good
Writing Makefile for Pg
[root(at)thinkpad-770x perl5]# make
mkdir blib
mkdir blib/lib
mkdir blib/arch
mkdir blib/arch/auto
mkdir blib/arch/auto/Pg
mkdir blib/lib/auto
mkdir blib/lib/auto/Pg
mkdir blib/man3
cp Pg.pm blib/lib/Pg.pm
AutoSplitting blib/lib/Pg.pm (blib/lib/auto/Pg)
/usr/bin/perl -I/usr/local/lib/perl5/5.6.0/i686-linux-thread
-I/usr/local/lib/perl5/5.6.0 /usr/local/lib/perl5/5.6.0/ExtUtils/xsubpp
-typemap /usr/local/lib/perl5/5.6.0/ExtUtils/typemap -typemap typemap
Pg.xs > Pg.xsc && mv Pg.xsc Pg.c
cc -c -I../libpq -I../../include -D_REENTRANT -fno-strict-aliasing
-I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2
-DVERSION=\"1.8.0\" -DXS_VERSION=\"1.8.0\" -fpic
-I/usr/local/lib/perl5/5.6.0/i686-linux-thread/CORE Pg.c
Pg.xs: In function `XS_Pg_PQprint':
Pg.xs:584: `na' undeclared (first use in this function)
Pg.xs:584: (Each undeclared identifier is reported only once
Pg.xs:584: for each function it appears in.)
Pg.xs: In function `XS_PG_results_fetchrow':
Pg.xs:1255: `sv_undef' undeclared (first use in this function)
Pg.xs: In function `XS_PG_results_print':
Pg.xs:1295: `na' undeclared (first use in this function)
make: *** [Pg.o] Error 1
[root(at)thinkpad-770x perl5]#

Any ideas? What're sv_undef and na supposed to be? (i.e. which includes
or whatever are missing?)

TIA

H.