Expand %Config variables only if explicitly so requested

during build time by PERL_BUILD_EXPAND_CONFIG_VARS.

Subject: Re: PATCH $Config::Config{ldlibpthname} in ext/DynaLoader/DynaLoader_pm.PL
Message-Id: <200010221847.LAA02167@smtp3.ActiveState.com>

p4raw-id: //depot/perl@7401

diff --git a/lib/lib_pm.PL b/lib/lib_pm.PL
index bb02106..66b4944 100644 (file)
--- a/lib/lib_pm.PL
+++ b/lib/lib_pm.PL
@@ -8,10 +8,30 @@ chdir dirname($0);
 my $file = basename($0, '.PL');
 $file =~ s!_(pm)$!.$1!i;
 
-my $Config_archname = defined($Config{'archname'}) ? $Config{'archname'} : '';
-my $Config_ver = defined($Config{'version'}) ? $Config{'version'} : '';
-my @Config_inc_version_list = defined($Config{'inc_version_list'}) ?
-  reverse split / /, $Config{'inc_version_list'} : ();
+my $useConfig;
+my $Config_archname;
+my $Config_version;
+my $Config_inc_version_list;
+
+# Expand the variables only if explicitly requested because
+# otherwise relocating Perl becomes much harder.
+
+if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS}) {
+    $useConfig = '';
+    $Config_archname = qq('$Config{archname}');
+    $Config_version  = qq('$Config{version}');
+    my @Config_inc_version_list =
+       reverse split / /, $Config{inc_version_list};
+    $Config_inc_version_list =
+       @Config_inc_version_list ?
+           qq(@Config_inc_version_list) : q(());
+} else {
+    $useConfig = 'use Config;';
+    $Config_archname = q($Config{archname});
+    $Config_version  = q($Config{version});
+    $Config_inc_version_list =
+             q(reverse split / /, qw($Config{inc_version_list}));
+}
  
 open OUT,">$file" or die "Can't create $file: $!";
  
@@ -26,9 +46,11 @@ package lib;
 # THIS FILE IS AUTOMATICALLY GENERATED FROM lib_pm.PL.
 # ANY CHANGES TO THIS FILE WILL BE OVERWRITTEN BY THE NEXT PERL BUILD.
 
-my \$archname = "$Config_archname";
-my \$ver = "$Config_ver";
-my \@inc_version_list = qw(@Config_inc_version_list);
+$useConfig
+
+my \$archname         = $Config_archname;
+my \$version          = $Config_version;
+my \@inc_version_list = $Config_inc_version_list;
 
 !GROK!THIS!
 print OUT <<'!NO!SUBS!';
@@ -57,9 +79,9 @@ sub import {
         }
        # Put a corresponding archlib directory infront of $_ if it
        # looks like $_ has an archlib directory below it.
-       unshift(@INC, "$_/$archname") if -d "$_/$archname/auto";
-       unshift(@INC, "$_/$ver") if -d "$_/$ver";
-       unshift(@INC, "$_/$ver/$archname") if -d "$_/$ver/$archname";
+       unshift(@INC, "$_/$archname")          if -d "$_/$archname/auto";
+       unshift(@INC, "$_/$version")           if -d "$_/$version";
+       unshift(@INC, "$_/$version/$archname") if -d "$_/$version/$archname";
     }
 
     # remove trailing duplicates
@@ -74,9 +96,9 @@ sub unimport {
     my %names;
     foreach (@_) {
        ++$names{$_};
-       ++$names{"$_/$archname"} if -d "$_/$archname/auto";
-       ++$names{"$_/$ver"} if -d "$_/$ver";
-       ++$names{"$_/$ver/$archname"} if -d "$_/$ver/$archname";
+       ++$names{"$_/$archname"}          if -d "$_/$archname/auto";
+       ++$names{"$_/$version"}           if -d "$_/$version";
+       ++$names{"$_/$version/$archname"} if -d "$_/$version/$archname";
     }
 
     # Remove ALL instances of each named directory.