mysql5 5.0.67_1+server - mysql_install_db errors

[edmond@…]

When running mysql_install_db errors occur:

mal:/opt/local/lib/mysql5 edmond% sudo -u mysql ./bin/mysql_install_db
FATAL ERROR: Could not find fill_help_tables.sql inside --basedir

When using --basedir you must point either into a MySQL binary
distribution directory or a compiled tree previously populated
by 'make install'
mal:/opt/local/lib/mysql5 root# sudo -u mysql ./bin/mysql_install_db --user=mysql
bindir = __PREFIX/bin
FATAL ERROR: Could not find fill_help_tables.sql inside --basedir

When using --basedir you must point either into a MySQL binary
distribution directory or a compiled tree previously populated
by 'make install'

Which is because of the following code:

if test -z "$basedir"
then  
  basedir="/opt/local"
  bindir="/opt/local/lib/mysql5/bin"
  mysqld="/opt/local/libexec/mysqld"
  pkgdatadir="/opt/local/share/mysql5/mysql"
else  
  bindir="$basedir/bin"
  # We set up bootstrap-specific paths later, so skip this for now
  if test "$cross_bootstrap" -eq 0
  then  

It looks like $basedir should be null when it reaches the above, but instead it is "__PREFIX/bin" which turns up nothing when searching for key files. Perhaps some substitution failed? I got it to work, by forcing the correct values in the script, but I'm guessing that's not intended.

[edmond@…]

The problem seems to be in the __PREFIX tag not getting converted to the actual prefix in the /opt/local/etc/my.cnf file.