[C++][Flight][OSX] Building 3rdparty grpc cannot find OpenSSL

[asfimport]

Without system grpc installed compiling grpc cannot find openssl:

Could NOT find OpenSSL, try to set the path to OpenSSL root folder in the
  system variable OPENSSL_ROOT_DIR (missing: OPENSSL_INCLUDE_DIR)
Call Stack (most recent call first):
  /usr/local/Cellar/cmake/3.14.5/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:378 (_FPHSA_FAILURE_MESSAGE)
  /usr/local/Cellar/cmake/3.14.5/share/cmake/Modules/FindOpenSSL.cmake:413 (find_package_handle_standard_args)
  cmake/ssl.cmake:45 (find_package)
  CMakeLists.txt:141 (include)

Passing ARROW_CMAKE_OPTION="-DOPENSSL_ROOT_DIR=$(brew --prefix openssl)" doesn't seem to get forwarded to build_grpc

'/usr/local/Cellar/cmake/3.14.5/bin/cmake' '-DCMAKE_BUILD_TYPE=RELEASE' '-DCMAKE_PREFIX_PATH=';/usr/local;/usr/local;/var/folders/cz/jrwncy5s5cb612sgwscd0z8h0000gn/T/arrow-0.14.0.XXXXX.I2yQzNGd/apache-arrow-0.14.0/cpp/thirdparty/cares_
ep-install;'' '-DgRPC_CARES_PROVIDER=package' '-DgRPC_GFLAGS_PROVIDER=package' '-DgRPC_PROTOBUF_PROVIDER=package' '-DgRPC_SSL_PROVIDER=package' '-DgRPC_ZLIB_PROVIDER=package' '-DCMAKE_CXX_FLAGS= -Qunused-arguments -fcolor-diagnostics -O3
-DNDEBUG -O3 -DNDEBUG -fPIC' '-DCMAKE_C_FLAGS= -Qunused-arguments -O3 -DNDEBUG -O3 -DNDEBUG -fPIC' '-DCMAKE_INSTALL_PREFIX=/var/folders/cz/jrwncy5s5cb612sgwscd0z8h0000gn/T/arrow-0.14.0.XXXXX.I2yQzNGd/apache-arrow-0.14.0/cpp/thirdparty/grp
c_ep-install' '-DCMAKE_INSTALL_LIBDIR=lib' '-DProtobuf_PROTOC_LIBRARY=/usr/local/lib/libprotoc.dylib' '-DBUILD_SHARED_LIBS=OFF' '-GUnix Makefiles' '/var/folders/cz/jrwncy5s5cb612sgwscd0z8h0000gn/T/arrow-0.14.0.XXXXX.I2yQzNGd/apache-arrow-
0.14.0/cpp/build/grpc_ep-prefix/src/grpc_ep'

Installing grpc with brew helps though.

Reporter: Krisztian Szucs / @kszucs
Assignee: Kouhei Sutou / @kou

PRs and other links:

• GitHub Pull Request #4795

_{Note: This issue was originally created as ARROW-5838. Please see the migration documentation for further details.}

[asfimport]

Krisztian Szucs / @kszucs:
Issue resolved by pull request 4795
#4795