how to install memcached via pecl?

Question

I'm trying to install memcached and am having some difficulty. Here's what I tried:

apt-get update
apt-get install memcached libmemcached-dev libzip-dev
pecl install memcached

pecl install memcached asked me a bunch of questions:

libmemcached directory [no] : /usr/include/libmemcached/
zlib directory [no] :
use system fastlz [no] :
enable igbinary serializer [no] :
enable msgpack serializer [no] :
enable json serializer [no] :
enable server protocol [no] :
enable sasl [yes] :
enable sessions [yes] :

I went with the default answers for each one, save for the first one, and got this error:

checking for libmemcached location... configure: error: Unable to find memcached.h under /usr/include/libmemcached/

ERROR: `/tmp/pear/temp/memcached/configure --with-php-config=/usr/local/bin/php-config --with-libmemcached-dir=/usr/include/libmemcached/ --with-zlib-dir=no --with-system-fastlz=no --enable-memcached-igbinary=no --enable-memcached-msgpack=no --enable-memcached-json=no --enable-memcached-protocol=no --enable-memcached-sasl=yes --enable-memcached-session=yes' failed

I do not understand this error. When I do find / -type f -name "memcached.h" I get this back:

/usr/include/libmemcached-1.0/struct/memcached.h
/usr/include/libmemcached-1.0/memcached.h
/usr/include/libmemcached/memcached.h

So find can find memcached.h in /usr/include/libmemcached/ but /tmp/pear/temp/memcached/configure can't? That doesn't make any sense.

I'm running all this in sudo bash so permissions shouldn't be an issue.

Any ideas?