Undefined reference to 'inflateInit2_'

Use the option -L<path> to tell the linker where to find libz.so.x.y.z.

For your reference: http://gcc.gnu.org/onlinedocs/gcc/Directory-Options.html

you can see where your zlib is installed like this :

/sbin/ldconfig -p| grep libz.so

it should find one or more entries if installed, otherwise it will return blank line