Merge pull request #5165 from ctiller/bring_back_gpr

BUILD

Makefile

binding.gyp

build.yaml

gRPC.podspec

grpc.gemspec

package.json

src/boringssl/gen_build_yaml.py

src/php/ext/grpc/config.m4

src/python/grpcio/grpc_core_dependencies.py

templates/BUILD.template

templates/Makefile.template

templates/gRPC.podspec.template

templates/tools/doxygen/Doxyfile.core.internal.template

templates/tools/doxygen/Doxyfile.core.template

templates/vsprojects/cpptest.props.template

test/core/bad_client/gen_build_yaml.py

test/core/bad_ssl/gen_build_yaml.py

test/core/end2end/gen_build_yaml.py

tools/doxygen/Doxyfile.core