Prior commit ad2a648 changed 'char *' to 'const char*' to match blead. This broke 5.8.X, which expected a non- constant file pointer in newXS. Subsequent iterations had logic that used 'const char*' for 5.9+ and 'char' for earlier perls, but this broke mod_perl, which expects file to be an assignable pointer. This commit reverts back to the 'char *' style used in perl 5.8.X. This should finally put RT#48104 to bed.