$PHP_AUTOCONF errors on mac os x 10.7.3 when trying to install pecl extensions

I am trying to setup my machine with pecl_http and memcache and in both cases, I get similar errors. This is on MAC OS X 10.7.3 (lion) and I also have XCODE installed on it. I also installed Zend Server community edition before running these commands and have CFLAGS='-arch i386 -arch x86_64' environment variables set

bash-3.2# **sudo pecl install pecl_http-1.7.1**
downloading pecl_http-1.7.1.tgz ...
Starting to download pecl_http-1.7.1.tgz (174,098 bytes)
.....................................done: 174,098 bytes
71 source files, building
running: phpize
Configuring for:
PHP Api Version:         20090626
Zend Module Api No:      20090626
Zend Extension Api No:   220090626
Cannot find autoconf. Please check your autoconf installation and the
**$PHP_AUTOCONF environment variable. Then, rerun this script.**
**ERROR: `phpize' failed**