Fix #326

`sys/param.h` is already conditionally included in `czmq_prelude.h`.

Signed-off-by: Shannen Saez <shannenlaptop@gmail.com>
Merge pull request #328 from shancat/sha1_windows

Fix #326
Merge pull request #327 from shancat/master

Add missing #defines for Android.
Fix Windows build.

Windows will see that `S_IREAD` & `S_IWRITE` aren't defined and try to
access `S_IRUSR` & `S_IWUSR` which don't exist on Windows.

Signed-off-by: Shannen Saez <shannenlaptop@gmail.com>