Fix windows build.

Declare an explicit dependency on libz for its headers. This works
on non-windows builds because libz appears to be in the default
include path.

Also, remove a doubly obsolete hack. Obsolete because we don't compile
the platform on cygwin any longer and obsolete because we don't use
-fvisibility=hidden any longer.

Change-Id: I85e6fc8dda32a0479fcf241b2dde8679e6b6688d
1 file changed