Cannot compile Perl with -Dusethreads

[Holger Marzen]

I have an old Linux system that's based on libc5. When I compile a
standard Perl (5.8.1 or 5.8.3) then I have no problems. But
Sendmail::Milter wants a threaded Perl, so I did

sh Configure -Dusethreads -d

The "make" fails with

|make[1]: Leaving directory `/usr/src/perl-5.8.3'
|
| Making DynaLoader (static)
|make[1]: Entering directory `/usr/src/perl-5.8.3/ext/DynaLoader'
|Can't locate ExtUtils/Command.pm in @INC (@INC contains:
|/usr/local/lib/perl5/5.8.3/i586-linux-thread-multi
|/usr/local/lib/perl5/5.8.3
|/usr/local/lib/perl5/site_perl/5.8.3/i586-linux-thread-multi
|/usr/local/lib/perl5/site_perl/5.8.3
|/usr/local/lib/perl5/site_perl/5.8.1 /usr/local/lib/perl5/site_perl .).
|BEGIN failed--compilation aborted.
|make[1]: *** [blib/lib/.exists] Error 2
|make[1]: Leaving directory `/usr/src/perl-5.8.3/ext/DynaLoader'
|make config failed, continuing anyway...
|make[1]: Entering directory `/usr/src/perl-5.8.3/ext/DynaLoader'
|Can't locate ExtUtils/Command.pm in @INC (@INC contains:
|/usr/local/lib/perl5/5.8.3/i586-linux-thread-multi
|/usr/local/lib/perl5/5.8.3
|/usr/local/lib/perl5/site_perl/5.8.3/i586-linux-thread-multi
|/usr/local/lib/perl5/site_perl/5.8.3
|/usr/local/lib/perl5/site_perl/5.8.1 /usr/local/lib/perl5/site_perl .).
|BEGIN failed--compilation aborted.
|make[1]: *** [blib/lib/.exists] Error 2
|make[1]: Leaving directory `/usr/src/perl-5.8.3/ext/DynaLoader'
|make: *** [lib/auto/DynaLoader/DynaLoader.a] Error 2

both with Perl 5.8.1 and 5.8.3. Is this a bug in the makefiles?
Is there a fix or workaround for this?