Continue #20506.

p4raw-id: //depot/perl@20508

diff --git a/lib/ExtUtils/MM_Unix.pm b/lib/ExtUtils/MM_Unix.pm
index f5a7ffd..423c3e9 100644 (file)
--- a/lib/ExtUtils/MM_Unix.pm
+++ b/lib/ExtUtils/MM_Unix.pm
@@ -3111,10 +3111,9 @@ sub pasthru {
     $sep .= "\\\n\t";
 
     foreach $key (qw(LIB LIBPERL_A LINKTYPE PREFIX OPTIMIZE INC DEFINE)) {
-       if ($key eq 'INC') {
+       if ($key eq 'INC' && defined(my $inc = $self->{INC})) {
            # For INC we need to prepend parent directory but
            # only iff the parent directory is not absolute.
-           my $inc = $self->{INC};
            my ($o, $i) = $Is_VMS ? ('/Include=', 'i') : ('-I', '');
            $inc =~ s!(?$i)$o(.+?)!$o.($self->file_name_is_absolute($1)?$1:$self->catdir($self->updir,$1))!eg;
            push @pasthru, "INC=\"$inc\"";