Reshuffle Makefile.PL a bit and add parallel-testing exception

Makefile.PL

@@ -8,23 +8,6 @@ use FindBin;
 use lib "$FindBin::Bin/lib";
 use DBIx::Class::Optional::Dependencies;
 
-# adjust ENV for $AUTHOR system() calls
-use Config;
-$ENV{PERL5LIB} = join ($Config{path_sep}, @INC);
-
-use Getopt::Long ();
-
-my $getopt = Getopt::Long::Parser->new(
-  config => [qw/gnu_getopt bundling_override no_ignore_case pass_through/]
-);
-my $args = {
-  skip_author_deps => undef,
-};
-$getopt->getoptions($args, 'skip_author_deps');
-if (@ARGV) {
-  warn "\nIgnoring unrecognized option(s): @ARGV\n\n";
-}
-
 # get cpanX --installdeps . to behave in a checkout (most users do not need
 # the deps for a full test suite run, and if they do - there's MI::AutoInstall
 # for that)
@@ -86,6 +69,40 @@ my $runtime_requires = {
   'File::Path'               => '2.07',
 };
 
+
+# Bail out on parallel testing
+if (
+  ($ENV{HARNESS_OPTIONS}||'') =~ / (?: ^ | \: ) j(\d+) /x
+    and
+  $1 > 1
+) { die <<EOP }
+
+******************************************************************************
+******************************************************************************
+***                                                                        ***
+***      PARALLEL TESTING DETECTED ( \$ENV{HARNESS_OPTIONS} = 'j$1' )        ***
+***                                                                        ***
+*** DBIC tests will fail. It is harder to make them parallel-friendly than ***
+*** it should be (though work is underway). In the meantime you will have  ***
+*** to adjust your environment and re-run the installation. Sorry!         ***
+***                                                                        ***
+******************************************************************************
+******************************************************************************
+
+EOP
+
+require Getopt::Long;
+my $getopt = Getopt::Long::Parser->new(
+  config => [qw/gnu_getopt bundling_override no_ignore_case pass_through/]
+);
+my $args = {
+  skip_author_deps => undef,
+};
+$getopt->getoptions($args, 'skip_author_deps');
+if (@ARGV) {
+  warn "\nIgnoring unrecognized option(s): @ARGV\n\n";
+}
+
 # this is so we can order requires alphabetically
 # copies are needed for author requires injection
 my $reqs = {
@@ -172,6 +189,10 @@ warn $optdep_msg if $Module::Install::AUTHOR;
 # re-create various autogenerated documentation bits
 if ($Module::Install::AUTHOR) {
 
+  # adjust ENV for $AUTHOR system() calls
+  require Config;
+  $ENV{PERL5LIB} = join ($Config::Config{path_sep}, @INC);
+
   print "Regenerating README\n";
   system('pod2text lib/DBIx/Class.pm > README');