Generate META files if not included

Resolves skaji#230

Generally allows installing from archives or git repositories.

lib/App/cpm/Worker/Installer.pm

@@ -213,9 +213,19 @@ sub fetch {
 
  chdir $dir or die;
 
- my $meta = $self->_load_metafile($distfile, 'META.json', 'META.yml');
+ my @accepted_meta_files = ['META.json', 'META.yml', 'MYMETA.json', 'MYMETA.yml'];
+
+ if (! grep -f, @accepted_meta_files && grep -f ['Makefile.PL', 'Build.PL']) {
+ $self->{logger}->log("Configuring distribution via Makefile.PL or Build.PL");
+ if (system("$^X Makefile.PL") != 0 && system("$^X Build.PL") != 0) {
+ $self->{logger}->log("Failed to configure distribution via Makefile.PL or Build.PL");
+ return;
+ }
+ }
+
+ my $meta = $self->_load_metafile($distfile, 'META.json', 'META.yml', 'MYMETA.json', 'MYMETA.yml');
  if (!$meta) {
- $self->{logger}->log("Distribution does not have META.json nor META.yml");
+ $self->{logger}->log("Distribution lacks both META.json and META.yml files, and neither MYMETA.json nor MYMETA.yml can be generated");
  return;
  }
  my $p = $meta->{provides} || $self->menlo->extract_packages($meta, ".");