Changes with Apache 2.0b1

  *) Cleaned out open_file from mod_file_cache, as apr now accepts

     the APR_XTHREAD argument to open a file for consumption by

     parallel threads on win32.  [William Rowe]

  *) Correct a bug in determining when we follow symlinks.  The code

     expected a stat -1 result, not an apr_status_t positive error.

     Also check if the APR_FINFO_USER fields are valid before we

     follow the link.  [William Rowe]

  *) Move initgroupgs, ap_uname2id and ap_gname2id from util.c to

     mpm_common.c.  These functions are only valid on some platforms,

     so they should not be in the main-line code. [Ryan Bloom]