I confirmed your observation on Darwin. What I don't understand yet is: Why is this file being created only on my Mac and not on my Linux?
The file appears to be created via config/auto/jit.pm. [parrot] 551 $ grep -n asmfun config/auto/jit.pm 86: copy_if_diff( $sjit, "src/asmfun.s" ); 87: $conf->data->set( asmfun_o => 'src/asmfun$(O)' ); 90: copy_if_diff( $asm, "src/asmfun.s" ); 91: $conf->data->set( asmfun_o => 'src/asmfun$(O)' ); 94: $conf->data->set( asmfun_o => '' ); On neither my Mac nor my Linux am I passing any JIT-related options to Configure.pl. So I don't understand why the file is being created on one OS and not on the other. I suspect that if we understood that, we'd be able to hone in on the reason why 'make realclean' fails to remove it on Darwin. kid51