zlib/CMakeLists: Fix check for unistd.h

The CMakeLists file for the static zlib checks for presence of
unistd.h, but it doesn't properly define HAVE_UNISTD_H if it's found.

This change adds the necessary preprocessor definition if unistd.h is
found.

Upstream zlib handles this with by configuring zconf.h with CMake:
https://github.com/madler/zlib/blob/cacf7f1d4e3d44d871b605da3b647f07d718623f/zconf.h.cmakein#L11

Dolphin's static version of zlib doesn't do this, which is why setting
Z_HAVE_UNISTD_H in zlib's CMakeLists.txt isn't enough.

This probably wasn't noticed since because most *nix systems will use
the shared zlib. Force use of the static zlib (comment out
find_package(ZLIB) in the root CMakeLists.txt) and you'll see implicit
function declaration warnings during its compilation.

0 files changed, 0 insertions, 0 deletions