diff --git a/lib/ExtUtils/MM_Unix.pm b/lib/ExtUtils/MM_Unix.pm
index 4e4326d5fb0c..34fec38db7bc 100644
--- a/lib/ExtUtils/MM_Unix.pm
+++ b/lib/ExtUtils/MM_Unix.pm
@@ -1921,7 +1921,8 @@ sub init_PERL {
     }
 
     # Are we building the core?
-    $self->{PERL_CORE} = 0 unless exists $self->{PERL_CORE};
+    $self->{PERL_CORE} = $ENV{PERL_CORE} unless exists $self->{PERL_CORE};
+    $self->{PERL_CORE} = 0               unless defined $self->{PERL_CORE};
 
     # How do we run perl?
     foreach my $perl (qw(PERL FULLPERL ABSPERL)) {
diff --git a/lib/ExtUtils/MM_Win32.pm b/lib/ExtUtils/MM_Win32.pm
index 3839c2404242..5e7f8e5f7670 100644
--- a/lib/ExtUtils/MM_Win32.pm
+++ b/lib/ExtUtils/MM_Win32.pm
@@ -168,7 +168,7 @@ sub init_others {
     $self->{DEV_NULL} ||= '> NUL';
 
     $self->{FIXIN}    ||= $self->{PERL_CORE} ? 
-      '$(PERLRUN) ../../win32/bin/pl2bat.pl' : 
+      "\$(PERLRUN) $self->{PERL_SRC}/win32/bin/pl2bat.pl" : 
       'pl2bat.bat';
 
     $self->{LD}     ||= $Config{ld} || 'link';