Bugfix: include files without trailing \n cause broken MANIFEST.SKIP …

…files

Internally, all lines are in an array, with each entry \n terminated.

However, this leads to a problem when the last line in in an included
file lacks a \n, as this gets stored as:

  [ "secondlastline\n", "lastline", "#!end included" ]

Which stringifies as:

  secondlastline
  lastline#!end included

And that lastline doesn't match the files its supposed to.

Closes GH Perl-Toolchain-Gang#14

lib/ExtUtils/Manifest.pm

@@ -504,6 +504,9 @@ sub _include_mskip_file {
     push @lines, "\n#!start included $mskip\n";
     push @lines, $_ while <M>;
     close M;
+    # Ensure the last line that came from an included skip file has a trailing \n
+    # or the one after it gets join()'d onto the end of it!
+    $lines[-1] =~ s/\n?$/\n/;
     push @lines, "#!end included $mskip\n\n";
     return @lines;
 }