Building with MinGW issue

Howdy,

I want to build Postgresql 9.1 under Windows with MinGW but I get this
error message whever I configure the project:

checking openssl/ssl.h usability... no
checking openssl/ssl.h presence... no
checking for openssl/ssl.h... no
configure: error: header file <openssl/ssl.h> is required for OpenSSL

How can I fix this issue?

P.S. I use the following options for configuring call:
$ ./configure --without-zlib --with-openssl
--with-includes=C:/OpenSSL-Win32/include
--with-libraries=C:/OpenSSL-Win32/lib
/MinGW

--
Best Regards,
Muhammad Bashir Al-Noimi