This config script ...

./configure \
--prefix=/usr/local \
--sbindir=/usr/sbin \
--sysconfdir=/etc/php3 \
--libdir=/usr/local/lib \
--sharedstatedir=/var/run \
--localstatedir=/var/run \
--with-apxs=/usr/sbin/apxs \
--with-x \
--with-mm=/usr/src/$MM \
--with-gd=shared,/usr \
--with-pgsql=shared,/usr \
--with-xml 
 
produces a php from which phpinfo() says.

php.ini path: /usr/local/lib

I'm sure the location of php.ini should be set by sysconfdir.!