I see this also; Jani's latest commit didn't fix it. Here's the config.log entry:

configure:51043: checking whether to include zlib support
configure:51244: checking for gzgets in -lz
configure:51263: gcc -o conftest -g -O2  -DLINUX=2 -DEAPI -DTARGET="apache" -DUSE_HSREGEX -DUSE_EXPAT -DSUPPORT_UTF8 -DXML_BYTE_ORDER=12 -L/usr/lib  -Wl,-rpath,/home/chuck/code/imap/lib -L/home/chuck/code/imap/lib -Wl,-rpath,/home/chuck/code/mcal/libmcal -L/home/chuck/code/mcal/libmcal conftest.c -lz  -lmysqlclient -lmcal -lldap -llber -lc-client -lcrypt -lresolv -lm -ldl -lnsl  -lresolv 1>&5
/usr/lib/libc-client.so: undefined reference to `mm_expunged'
/usr/lib/libc-client.so: undefined reference to `mm_diskerror'
/usr/lib/libc-client.so: undefined reference to `mm_lsub'
/usr/lib/libc-client.so: undefined reference to `mm_flags'
/usr/lib/libc-client.so: undefined reference to `mm_fatal'
/usr/lib/libc-client.so: undefined reference to `mm_nocritical'
/usr/lib/libc-client.so: undefined reference to `mm_notify'
/usr/lib/libc-client.so: undefined reference to `mm_searched'
/usr/lib/libc-client.so: undefined reference to `mm_status'
/usr/lib/libc-client.so: undefined reference to `mm_login'
/usr/lib/libc-client.so: undefined reference to `mm_list'
/usr/lib/libc-client.so: undefined reference to `mm_critical'
/usr/lib/libc-client.so: undefined reference to `mm_exists'
/usr/lib/libc-client.so: undefined reference to `mm_log'
/usr/lib/libc-client.so: undefined reference to `mm_dlog'
collect2: ld returned 1 exit status
configure: failed program was:
#line 51252 "configure"
#include "confdefs.h"
/* Override any gcc2 internal prototype to avoid an error.  */
/* We use char because int might match the return type of a gcc2
    builtin and then its argument prototype would still apply.  */
char gzgets();

int main() {
gzgets()
; return 0; }

This should be fixed now.
Reopen if not.

--Jani

confirmed fix