output for: ./configure pkg_cv_openssl_LIBS='-lssl -lcrypto'

checking for g++... g++
checking whether the C++ compiler works... yes
checking for C++ compiler default output file name... a.exe
checking for suffix of executables... .exe
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C++ compiler... yes
checking whether g++ accepts -g... yes
checking for a BSD-compatible install... /usr/bin/install -c
checking for grep that handles long lines and -e... /usr/bin/grep
checking for a sed that does not truncate output... /usr/bin/sed
checking build system type... i686-pc-cygwin
checking host system type... i686-pc-cygwin
checking for special C compiler options needed for large files... no
checking for _FILE_OFFSET_BITS value needed for large files... no
checking whether the -Werror option is usable... yes
checking for simple visibility declarations... no
checking for getopt_long in -lgnugetopt... no
checking for lstat... yes
checking for getopt_long... yes
checking for getphassphrase... no
checking for pkg-config... /usr/bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for library containing dlopen... none required
checking for the pthreads library -lpthreads... no
checking whether pthreads work without any flags... yes
checking for joinable pthread attribute... PTHREAD_CREATE_JOINABLE
checking if more special flags are required for pthreads... no
checking for PTHREAD_PRIO_INHERIT... no
checking for xlc_r... no
checking for cc_r... no
checking for openssl... yes
checking for iconv... no
checking for iconv_open in -liconv... no
configure: WARNING: libiconv was not found, disabling the charset module
checking for GNU make... /usr/bin/make
configure: creating ./config.status
config.status: creating Makefile
config.status: creating znc-config
config.status: creating znc-buildmod
config.status: creating man/Makefile
config.status: creating znc.pc
config.status: creating znc-uninstalled.pc
config.status: creating modules/Makefile
config.status: creating test/Makefile
config.status: creating include/znc/zncconfig.h
config.status: include/znc/zncconfig.h is unchanged

ZNC 0.205 configured

prefix:       /usr/local
debug:        no
ipv6:         yes
openssl:      yes
dns:          threads
perl:         no
python:       no
swig:         no
sasl:         no
tcl:          no
charset:      no
run from src: no

Now you can run "make" to compile ZNC