+my @need_relocation;
+
+if (fetch_string({},'userelocatableinc')) {
+ foreach my $what (qw(prefixexp
+
+ archlibexp
+ html1direxp
+ html3direxp
+ man1direxp
+ man3direxp
+ privlibexp
+ scriptdirexp
+ sitearchexp
+ sitebinexp
+ sitehtml1direxp
+ sitehtml3direxp
+ sitelibexp
+ siteman1direxp
+ siteman3direxp
+ sitescriptexp
+ vendorarchexp
+ vendorbinexp
+ vendorhtml1direxp
+ vendorhtml3direxp
+ vendorlibexp
+ vendorman1direxp
+ vendorman3direxp
+ vendorscriptexp
+
+ siteprefixexp
+ sitelib_stem
+ vendorlib_stem
+
+ installarchlib
+ installhtml1dir
+ installhtml3dir
+ installman1dir
+ installman3dir
+ installprefix
+ installprefixexp
+ installprivlib
+ installscript
+ installsitearch
+ installsitebin
+ installsitehtml1dir
+ installsitehtml3dir
+ installsitelib
+ installsiteman1dir
+ installsiteman3dir
+ installsitescript
+ installvendorarch
+ installvendorbin
+ installvendorhtml1dir
+ installvendorhtml3dir
+ installvendorlib
+ installvendorman1dir
+ installvendorman3dir
+ installvendorscript
+ )) {
+ push @need_relocation, $what if fetch_string({}, $what) =~ m!^\.\.\./!;
+ }
+}
+
+my %need_relocation;
+@need_relocation{@need_relocation} = @need_relocation;
+
+# This can have .../ anywhere:
+if (fetch_string({}, 'otherlibdirs') =~ m!\.\.\./!) {
+ $need_relocation{otherlibdirs} = 'otherlibdirs';
+}
+
+my $relocation_code = <<'EOT';
+
+sub relocate_inc {
+ my $libdir = shift;
+ return $libdir unless $libdir =~ s!^\.\.\./!!;
+ my $prefix = $^X;
+ if ($prefix =~ s!/[^/]*$!!) {
+ while ($libdir =~ m!^\.\./!) {
+ # Loop while $libdir starts "../" and $prefix still has a trailing
+ # directory
+ last unless $prefix =~ s!/([^/]+)$!!;
+ # but bail out if the directory we picked off the end of $prefix is .
+ # or ..
+ if ($1 eq '.' or $1 eq '..') {
+ # Undo! This should be rare, hence code it this way rather than a
+ # check each time before the s!!! above.
+ $prefix = "$prefix/$1";
+ last;
+ }
+ # Remove that leading ../ and loop again
+ substr ($libdir, 0, 3, '');
+ }
+ $libdir = "$prefix/$libdir";
+ }
+ $libdir;
+}
+EOT
+
+if (%need_relocation) {
+ my $relocations_in_common;
+ # otherlibdirs only features in the hash
+ foreach (keys %need_relocation) {
+ $relocations_in_common++ if $Common{$_};
+ }
+ if ($relocations_in_common) {
+ $config_txt .= $relocation_code;
+ } else {
+ $heavy_txt .= $relocation_code;
+ }
+}
+
+$heavy_txt .= join('', @non_v) . "\n";