php-4.3.1/pear/install-pear.php not respecting INSTALL_ROOT

i am trying to make an rpm with php-4.3.1. things are going swimmingly until we get to install pear. in install-pear.php i added echo's for $install_root and $reg_dir, and i see the INSTALL_ROOT envvar being used: <pre> $ export INSTALL_ROOT=/var/tmp/php-root/ $ ./BUILD/php-4.3.1/build-cgi/sapi/cli/php $PEAR_INSTALL_FLAGS ./BUILD/php-4.3.1/pear/install-pear.php |head install root: /var/tmp/php-root/ reg_dir: /var/tmp/php-root//usr/share/pear Warning: mkdir(/usr/share/pear) [http://www.php.net/function.mkdir]: Permission denied in /home/service/rpm/BUILD/php-4.3.1/pear/System.php on line 236 Warning: mkdir(/usr/share/pear/.registry) [http://www.php.net/function.mkdir]: No such file or directory in /home/service/rpm/BUILD/php-4.3.1/pear/System.php on line 236 Warning: mkdir(/usr/share/pear) [http://www.php.net/function.mkdir]: Permission denied in /home/service/rpm/BUILD/php-4.3.1/pear/System.php on line 236 Warning: mkdir(/usr/share/pear/.registry) [http://www.php.net/function.mkdir]: No such file or directory in /home/service/rpm/BUILD/php-4.3.1/pear/System.php on line 236 </pre> yeah well you're supposed to be doing mkdir in the INSTALL_ROOT. further i print_r()'d the pear_installer obj. it has the install_root prefix for the registry. but in config=>configuration=>default=>{php_dir|ext_dir|doc_dir|etc..} the install_root is not there, and there is nothing besides default in the configuration obj. am i close? i don't know much about pear except for the above.