[Dovecot] rc15 'configure' fails at "unexpected token `SSL,'"

[snowcrash+dovecot]

i'm building dovecot-1.0.rc15 on osx.

when i,

 ./configure --with-ssl=openssl --with-ssldir=/etc/ssl_certs
--disable-static --enable-shared --disable-maintainer-mode
--disable-ipv6 --with-mysql --with-sql-drivers=mysql --with-deliver
--with-pop3d --with-storages=maildir,mbox --disable-debug

it fails at,
	...
	checking how to hardcode library paths into programs... immediate
	appending configuration tag "F77" to libtool
	./configure: line 20184: AM_ICONV: command not found
	checking for strings.h... (cached) yes
	checking for stdint.h... (cached) yes
	...
	checking whether va_lists can be copied by value... yes
	./configure: line 26434: syntax error near unexpected token `SSL,'
	./configure: line 26434: `    PKG_CHECK_MODULES(SSL, openssl)'

i've checked the cvs co of the 1.0-branch, and the same problem exists.

any help?

thanks.