Incomplete zlib.gyp

[targos]

V8 now has a dependency on a Chromium's fork of zlib.
I made a minimal port of the GN file to GYP that works on my Linux machine but it is not enough.

https://github.com/nodejs/node-v8/blob/canary/tools/v8_gypfiles/zlib.gyp
The gyp file for our copy of zlib: https://github.com/nodejs/node-v8/blob/canary/deps/zlib/zlib.gyp

https://ci.nodejs.org/job/node-cross-compile/26378/nodes=cross-compiler-armv7-gcc-6/console

10:49:01 python ./configure --verbose  --dest-cpu=arm
10:49:03 gyp: Dependency '/home/iojs/build/workspace/node-cross-compile/tools/v8_gypfiles/zlib.gyp:zlib#host' not found while trying to load target /home/iojs/build/workspace/node-cross-compile/tools/v8_gypfiles/v8.gyp:v8_base_without_compiler#host

[targos]

The include bug is fixed.