If whilst compiling apache-tools one encounters:

libtool: link: cannot find the library `/usr/lib/libapr-1.la' or unhandled argument `/usr/lib/libapr-1.la'
make[1]: *** [htpasswd] Error 1
make[1]: Leaving directory `/var/tmp/portage/app-admin/apache-tools-2.2.21/work/httpd-2.2.21/support'
make: *** [all-recursive] Error 1
 * ERROR: app-admin/apache-tools-2.2.21 failed (compile phase):
 *   emake failed
 * 
 * If you need support, post the output of 'emerge --info =app-admin/apache-tools-2.2.21',
 * the complete build log and the output of 'emerge -pqv =app-admin/apache-tools-2.2.21'.
 * The complete build log is located at '/var/tmp/portage/app-admin/apache-tools-2.2.21/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/app-admin/apache-tools-2.2.21/temp/environment'.
 * S: '/var/tmp/portage/app-admin/apache-tools-2.2.21/work/httpd-2.2.21'

Your version of libapr is out of date. Update it:

# emerge --update apr apr-util --ask

Or append --deep when updating apache or apache-tools.