RFR: JDK-8196879: Forgot to add file in JDK-8196803

[Erik Joelsson]

When pushing JDK-8196803 just now, I forgot to add the zlib.h file. 
Please review this correction.

Bug: https://bugs.openjdk.java.net/browse/JDK-8196879
Webrev: http://cr.openjdk.java.net/~erikj/8196879/webrev.01/

/Erik