Merge pull request #4812 from ctiller/integrate-zlib

Makefile

src/zlib/gen_build_yaml.py

templates/Makefile.template

templates/tools/run_tests/sources_and_headers.json.template

templates/vsprojects/buildtests_c.sln.template

tools/buildgen/bunch.py

tools/buildgen/generate_build_additions.sh

tools/buildgen/plugins/expand_bin_attrs.py

tools/run_tests/sources_and_headers.json

vsprojects/buildtests_c.sln

vsprojects/grpc.sln

vsprojects/vcxproj/z/z.vcxproj

vsprojects/vcxproj/z/z.vcxproj.filters