追記:これ書いて、バグレポートしたとたんに4.50をかましてくれたよ。mlehman++。(まだコンパイル通るかどうかみてない)

このパッチで通ると思うよ。たぶん作者がperl 5.8でテストするの忘れてるだけだと思われ。ちなみに最初のPL_parser云々はたぶんそのまま消しちゃっても大丈夫。
--- Coro-4.49/Coro/State.xs 2008-04-07 02:47:38.000000000 +0900 +++ Coro-4.49.hacked/Coro/State.xs 2008-04-10 17:29:34.000000000 +0900 @@ -738,7 +738,7 @@ PL_localizing = 0; PL_dirty = 0; PL_restartop = 0; -#if !PERL_VERSION_ATLEAST (5,10,0) +#if PERL_VERSION_ATLEAST (5,10,0) PL_parser = 0; #endif @@ -1132,7 +1132,7 @@ croak ("Coro::State::transfer called with destroyed next Coro::State, but can only transfer to inactive states"); #if !PERL_VERSION_ATLEAST (5,10,0) - if (expect_false (PL_lex_state != LEX_NOTPARSING) + if (expect_false (PL_lex_state != LEX_NOTPARSING)) croak ("Coro::State::transfer called while parsing, but this is not supported"); #endif }