Adding support for loading the SSL roots from an environment variable.

- Had to add support for files and environment variables as well.
- I can't compile on windows so I'm sure there will be some issues.
- Tested end-to-end with the simple ssl fullstack test.
diff --git a/Makefile b/Makefile
index a3f1aaf..7f4c7dc 100644
--- a/Makefile
+++ b/Makefile
@@ -336,6 +336,8 @@
 gpr_histogram_test: bins/$(CONFIG)/gpr_histogram_test
 gpr_host_port_test: bins/$(CONFIG)/gpr_host_port_test
 gpr_log_test: bins/$(CONFIG)/gpr_log_test
+gpr_file_test: bins/$(CONFIG)/gpr_file_test
+gpr_env_test: bins/$(CONFIG)/gpr_env_test
 gpr_slice_buffer_test: bins/$(CONFIG)/gpr_slice_buffer_test
 gpr_slice_test: bins/$(CONFIG)/gpr_slice_test
 gpr_string_test: bins/$(CONFIG)/gpr_string_test
@@ -568,7 +570,7 @@
 
 buildtests: buildtests_c buildtests_cxx
 
-buildtests_c: privatelibs_c bins/$(CONFIG)/alarm_heap_test bins/$(CONFIG)/alarm_list_test bins/$(CONFIG)/alarm_test bins/$(CONFIG)/alpn_test bins/$(CONFIG)/bin_encoder_test bins/$(CONFIG)/census_hash_table_test bins/$(CONFIG)/census_statistics_multiple_writers_circular_buffer_test bins/$(CONFIG)/census_statistics_multiple_writers_test bins/$(CONFIG)/census_statistics_performance_test bins/$(CONFIG)/census_statistics_quick_test bins/$(CONFIG)/census_statistics_small_log_test bins/$(CONFIG)/census_stub_test bins/$(CONFIG)/census_window_stats_test bins/$(CONFIG)/chttp2_status_conversion_test bins/$(CONFIG)/chttp2_stream_encoder_test bins/$(CONFIG)/chttp2_stream_map_test bins/$(CONFIG)/chttp2_transport_end2end_test bins/$(CONFIG)/dualstack_socket_test bins/$(CONFIG)/echo_client bins/$(CONFIG)/echo_server bins/$(CONFIG)/echo_test bins/$(CONFIG)/fd_posix_test bins/$(CONFIG)/fling_client bins/$(CONFIG)/fling_server bins/$(CONFIG)/fling_stream_test bins/$(CONFIG)/fling_test bins/$(CONFIG)/gpr_cancellable_test bins/$(CONFIG)/gpr_cmdline_test bins/$(CONFIG)/gpr_histogram_test bins/$(CONFIG)/gpr_host_port_test bins/$(CONFIG)/gpr_log_test bins/$(CONFIG)/gpr_slice_buffer_test bins/$(CONFIG)/gpr_slice_test bins/$(CONFIG)/gpr_string_test bins/$(CONFIG)/gpr_sync_test bins/$(CONFIG)/gpr_thd_test bins/$(CONFIG)/gpr_time_test bins/$(CONFIG)/gpr_useful_test bins/$(CONFIG)/grpc_base64_test bins/$(CONFIG)/grpc_byte_buffer_reader_test bins/$(CONFIG)/grpc_channel_stack_test bins/$(CONFIG)/grpc_completion_queue_test bins/$(CONFIG)/grpc_credentials_test bins/$(CONFIG)/grpc_json_token_test bins/$(CONFIG)/grpc_stream_op_test bins/$(CONFIG)/hpack_parser_test bins/$(CONFIG)/hpack_table_test bins/$(CONFIG)/httpcli_format_request_test bins/$(CONFIG)/httpcli_parser_test bins/$(CONFIG)/httpcli_test bins/$(CONFIG)/json_rewrite bins/$(CONFIG)/json_rewrite_test bins/$(CONFIG)/json_test bins/$(CONFIG)/lame_client_test bins/$(CONFIG)/message_compress_test bins/$(CONFIG)/metadata_buffer_test bins/$(CONFIG)/murmur_hash_test bins/$(CONFIG)/no_server_test bins/$(CONFIG)/poll_kick_posix_test bins/$(CONFIG)/resolve_address_test bins/$(CONFIG)/secure_endpoint_test bins/$(CONFIG)/sockaddr_utils_test bins/$(CONFIG)/tcp_client_posix_test bins/$(CONFIG)/tcp_posix_test bins/$(CONFIG)/tcp_server_posix_test bins/$(CONFIG)/time_averaged_stats_test bins/$(CONFIG)/time_test bins/$(CONFIG)/timeout_encoding_test bins/$(CONFIG)/transport_metadata_test bins/$(CONFIG)/chttp2_fake_security_cancel_after_accept_test bins/$(CONFIG)/chttp2_fake_security_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_fake_security_cancel_after_invoke_test bins/$(CONFIG)/chttp2_fake_security_cancel_before_invoke_test bins/$(CONFIG)/chttp2_fake_security_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_fake_security_census_simple_request_test bins/$(CONFIG)/chttp2_fake_security_disappearing_server_test bins/$(CONFIG)/chttp2_fake_security_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_fake_security_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_fake_security_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_fake_security_invoke_large_request_test bins/$(CONFIG)/chttp2_fake_security_max_concurrent_streams_test bins/$(CONFIG)/chttp2_fake_security_no_op_test bins/$(CONFIG)/chttp2_fake_security_ping_pong_streaming_test bins/$(CONFIG)/chttp2_fake_security_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_fake_security_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_fake_security_request_response_with_payload_test bins/$(CONFIG)/chttp2_fake_security_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_fake_security_simple_delayed_request_test bins/$(CONFIG)/chttp2_fake_security_simple_request_test bins/$(CONFIG)/chttp2_fake_security_thread_stress_test bins/$(CONFIG)/chttp2_fake_security_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_fullstack_cancel_after_accept_test bins/$(CONFIG)/chttp2_fullstack_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_fullstack_cancel_after_invoke_test bins/$(CONFIG)/chttp2_fullstack_cancel_before_invoke_test bins/$(CONFIG)/chttp2_fullstack_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_fullstack_census_simple_request_test bins/$(CONFIG)/chttp2_fullstack_disappearing_server_test bins/$(CONFIG)/chttp2_fullstack_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_fullstack_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_fullstack_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_fullstack_invoke_large_request_test bins/$(CONFIG)/chttp2_fullstack_max_concurrent_streams_test bins/$(CONFIG)/chttp2_fullstack_no_op_test bins/$(CONFIG)/chttp2_fullstack_ping_pong_streaming_test bins/$(CONFIG)/chttp2_fullstack_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_fullstack_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_fullstack_request_response_with_payload_test bins/$(CONFIG)/chttp2_fullstack_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_fullstack_simple_delayed_request_test bins/$(CONFIG)/chttp2_fullstack_simple_request_test bins/$(CONFIG)/chttp2_fullstack_thread_stress_test bins/$(CONFIG)/chttp2_fullstack_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_after_accept_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_after_invoke_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_before_invoke_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_census_simple_request_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_disappearing_server_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_invoke_large_request_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_max_concurrent_streams_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_no_op_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_ping_pong_streaming_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_payload_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_simple_delayed_request_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_simple_request_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_thread_stress_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_after_accept_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_after_invoke_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_before_invoke_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_census_simple_request_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_disappearing_server_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_invoke_large_request_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_max_concurrent_streams_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_no_op_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_ping_pong_streaming_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_payload_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_simple_delayed_request_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_simple_request_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_thread_stress_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_socket_pair_cancel_after_accept_test bins/$(CONFIG)/chttp2_socket_pair_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_socket_pair_cancel_after_invoke_test bins/$(CONFIG)/chttp2_socket_pair_cancel_before_invoke_test bins/$(CONFIG)/chttp2_socket_pair_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_socket_pair_census_simple_request_test bins/$(CONFIG)/chttp2_socket_pair_disappearing_server_test bins/$(CONFIG)/chttp2_socket_pair_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_socket_pair_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_socket_pair_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_socket_pair_invoke_large_request_test bins/$(CONFIG)/chttp2_socket_pair_max_concurrent_streams_test bins/$(CONFIG)/chttp2_socket_pair_no_op_test bins/$(CONFIG)/chttp2_socket_pair_ping_pong_streaming_test bins/$(CONFIG)/chttp2_socket_pair_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_request_response_with_payload_test bins/$(CONFIG)/chttp2_socket_pair_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_simple_delayed_request_test bins/$(CONFIG)/chttp2_socket_pair_simple_request_test bins/$(CONFIG)/chttp2_socket_pair_thread_stress_test bins/$(CONFIG)/chttp2_socket_pair_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_accept_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_invoke_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_before_invoke_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_census_simple_request_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_disappearing_server_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_invoke_large_request_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_max_concurrent_streams_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_no_op_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_ping_pong_streaming_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_payload_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_delayed_request_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_request_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_thread_stress_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_writes_done_hangs_with_pending_read_test
+buildtests_c: privatelibs_c bins/$(CONFIG)/alarm_heap_test bins/$(CONFIG)/alarm_list_test bins/$(CONFIG)/alarm_test bins/$(CONFIG)/alpn_test bins/$(CONFIG)/bin_encoder_test bins/$(CONFIG)/census_hash_table_test bins/$(CONFIG)/census_statistics_multiple_writers_circular_buffer_test bins/$(CONFIG)/census_statistics_multiple_writers_test bins/$(CONFIG)/census_statistics_performance_test bins/$(CONFIG)/census_statistics_quick_test bins/$(CONFIG)/census_statistics_small_log_test bins/$(CONFIG)/census_stub_test bins/$(CONFIG)/census_window_stats_test bins/$(CONFIG)/chttp2_status_conversion_test bins/$(CONFIG)/chttp2_stream_encoder_test bins/$(CONFIG)/chttp2_stream_map_test bins/$(CONFIG)/chttp2_transport_end2end_test bins/$(CONFIG)/dualstack_socket_test bins/$(CONFIG)/echo_client bins/$(CONFIG)/echo_server bins/$(CONFIG)/echo_test bins/$(CONFIG)/fd_posix_test bins/$(CONFIG)/fling_client bins/$(CONFIG)/fling_server bins/$(CONFIG)/fling_stream_test bins/$(CONFIG)/fling_test bins/$(CONFIG)/gpr_cancellable_test bins/$(CONFIG)/gpr_cmdline_test bins/$(CONFIG)/gpr_histogram_test bins/$(CONFIG)/gpr_host_port_test bins/$(CONFIG)/gpr_log_test bins/$(CONFIG)/gpr_file_test bins/$(CONFIG)/gpr_env_test bins/$(CONFIG)/gpr_slice_buffer_test bins/$(CONFIG)/gpr_slice_test bins/$(CONFIG)/gpr_string_test bins/$(CONFIG)/gpr_sync_test bins/$(CONFIG)/gpr_thd_test bins/$(CONFIG)/gpr_time_test bins/$(CONFIG)/gpr_useful_test bins/$(CONFIG)/grpc_base64_test bins/$(CONFIG)/grpc_byte_buffer_reader_test bins/$(CONFIG)/grpc_channel_stack_test bins/$(CONFIG)/grpc_completion_queue_test bins/$(CONFIG)/grpc_credentials_test bins/$(CONFIG)/grpc_json_token_test bins/$(CONFIG)/grpc_stream_op_test bins/$(CONFIG)/hpack_parser_test bins/$(CONFIG)/hpack_table_test bins/$(CONFIG)/httpcli_format_request_test bins/$(CONFIG)/httpcli_parser_test bins/$(CONFIG)/httpcli_test bins/$(CONFIG)/json_rewrite bins/$(CONFIG)/json_rewrite_test bins/$(CONFIG)/json_test bins/$(CONFIG)/lame_client_test bins/$(CONFIG)/message_compress_test bins/$(CONFIG)/metadata_buffer_test bins/$(CONFIG)/murmur_hash_test bins/$(CONFIG)/no_server_test bins/$(CONFIG)/poll_kick_posix_test bins/$(CONFIG)/resolve_address_test bins/$(CONFIG)/secure_endpoint_test bins/$(CONFIG)/sockaddr_utils_test bins/$(CONFIG)/tcp_client_posix_test bins/$(CONFIG)/tcp_posix_test bins/$(CONFIG)/tcp_server_posix_test bins/$(CONFIG)/time_averaged_stats_test bins/$(CONFIG)/time_test bins/$(CONFIG)/timeout_encoding_test bins/$(CONFIG)/transport_metadata_test bins/$(CONFIG)/chttp2_fake_security_cancel_after_accept_test bins/$(CONFIG)/chttp2_fake_security_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_fake_security_cancel_after_invoke_test bins/$(CONFIG)/chttp2_fake_security_cancel_before_invoke_test bins/$(CONFIG)/chttp2_fake_security_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_fake_security_census_simple_request_test bins/$(CONFIG)/chttp2_fake_security_disappearing_server_test bins/$(CONFIG)/chttp2_fake_security_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_fake_security_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_fake_security_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_fake_security_invoke_large_request_test bins/$(CONFIG)/chttp2_fake_security_max_concurrent_streams_test bins/$(CONFIG)/chttp2_fake_security_no_op_test bins/$(CONFIG)/chttp2_fake_security_ping_pong_streaming_test bins/$(CONFIG)/chttp2_fake_security_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_fake_security_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_fake_security_request_response_with_payload_test bins/$(CONFIG)/chttp2_fake_security_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_fake_security_simple_delayed_request_test bins/$(CONFIG)/chttp2_fake_security_simple_request_test bins/$(CONFIG)/chttp2_fake_security_thread_stress_test bins/$(CONFIG)/chttp2_fake_security_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_fullstack_cancel_after_accept_test bins/$(CONFIG)/chttp2_fullstack_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_fullstack_cancel_after_invoke_test bins/$(CONFIG)/chttp2_fullstack_cancel_before_invoke_test bins/$(CONFIG)/chttp2_fullstack_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_fullstack_census_simple_request_test bins/$(CONFIG)/chttp2_fullstack_disappearing_server_test bins/$(CONFIG)/chttp2_fullstack_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_fullstack_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_fullstack_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_fullstack_invoke_large_request_test bins/$(CONFIG)/chttp2_fullstack_max_concurrent_streams_test bins/$(CONFIG)/chttp2_fullstack_no_op_test bins/$(CONFIG)/chttp2_fullstack_ping_pong_streaming_test bins/$(CONFIG)/chttp2_fullstack_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_fullstack_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_fullstack_request_response_with_payload_test bins/$(CONFIG)/chttp2_fullstack_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_fullstack_simple_delayed_request_test bins/$(CONFIG)/chttp2_fullstack_simple_request_test bins/$(CONFIG)/chttp2_fullstack_thread_stress_test bins/$(CONFIG)/chttp2_fullstack_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_after_accept_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_after_invoke_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_before_invoke_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_census_simple_request_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_disappearing_server_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_invoke_large_request_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_max_concurrent_streams_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_no_op_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_ping_pong_streaming_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_payload_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_simple_delayed_request_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_simple_request_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_thread_stress_test bins/$(CONFIG)/chttp2_simple_ssl_fullstack_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_after_accept_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_after_invoke_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_before_invoke_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_census_simple_request_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_disappearing_server_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_invoke_large_request_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_max_concurrent_streams_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_no_op_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_ping_pong_streaming_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_payload_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_simple_delayed_request_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_simple_request_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_thread_stress_test bins/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_socket_pair_cancel_after_accept_test bins/$(CONFIG)/chttp2_socket_pair_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_socket_pair_cancel_after_invoke_test bins/$(CONFIG)/chttp2_socket_pair_cancel_before_invoke_test bins/$(CONFIG)/chttp2_socket_pair_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_socket_pair_census_simple_request_test bins/$(CONFIG)/chttp2_socket_pair_disappearing_server_test bins/$(CONFIG)/chttp2_socket_pair_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_socket_pair_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_socket_pair_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_socket_pair_invoke_large_request_test bins/$(CONFIG)/chttp2_socket_pair_max_concurrent_streams_test bins/$(CONFIG)/chttp2_socket_pair_no_op_test bins/$(CONFIG)/chttp2_socket_pair_ping_pong_streaming_test bins/$(CONFIG)/chttp2_socket_pair_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_request_response_with_payload_test bins/$(CONFIG)/chttp2_socket_pair_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_simple_delayed_request_test bins/$(CONFIG)/chttp2_socket_pair_simple_request_test bins/$(CONFIG)/chttp2_socket_pair_thread_stress_test bins/$(CONFIG)/chttp2_socket_pair_writes_done_hangs_with_pending_read_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_accept_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_accept_and_writes_closed_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_invoke_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_before_invoke_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_in_a_vacuum_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_census_simple_request_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_disappearing_server_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_early_server_shutdown_finishes_inflight_calls_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_early_server_shutdown_finishes_tags_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_graceful_server_shutdown_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_invoke_large_request_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_max_concurrent_streams_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_no_op_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_ping_pong_streaming_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_binary_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_payload_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_trailing_metadata_and_payload_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_delayed_request_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_request_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_thread_stress_test bins/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_writes_done_hangs_with_pending_read_test
 
 buildtests_cxx: privatelibs_cxx bins/$(CONFIG)/channel_arguments_test bins/$(CONFIG)/credentials_test bins/$(CONFIG)/end2end_test bins/$(CONFIG)/interop_client bins/$(CONFIG)/interop_server bins/$(CONFIG)/qps_client bins/$(CONFIG)/qps_server bins/$(CONFIG)/status_test bins/$(CONFIG)/sync_client_async_server_test bins/$(CONFIG)/thread_pool_test bins/$(CONFIG)/tips_client bins/$(CONFIG)/tips_client_test
 
@@ -629,6 +631,10 @@
 	$(Q) ./bins/$(CONFIG)/gpr_host_port_test || ( echo test gpr_host_port_test failed ; exit 1 )
 	$(E) "[RUN]     Testing gpr_log_test"
 	$(Q) ./bins/$(CONFIG)/gpr_log_test || ( echo test gpr_log_test failed ; exit 1 )
+	$(E) "[RUN]     Testing gpr_file_test"
+	$(Q) ./bins/$(CONFIG)/gpr_file_test || ( echo test gpr_file_test failed ; exit 1 )
+	$(E) "[RUN]     Testing gpr_env_test"
+	$(Q) ./bins/$(CONFIG)/gpr_env_test || ( echo test gpr_env_test failed ; exit 1 )
 	$(E) "[RUN]     Testing gpr_slice_buffer_test"
 	$(Q) ./bins/$(CONFIG)/gpr_slice_buffer_test || ( echo test gpr_slice_buffer_test failed ; exit 1 )
 	$(E) "[RUN]     Testing gpr_slice_test"
@@ -1210,6 +1216,11 @@
     src/core/support/cmdline.c \
     src/core/support/cpu_linux.c \
     src/core/support/cpu_posix.c \
+    src/core/support/env_posix.c \
+    src/core/support/env_win32.c \
+    src/core/support/file.c \
+    src/core/support/file_posix.c \
+    src/core/support/file_win32.c \
     src/core/support/histogram.c \
     src/core/support/host_port.c \
     src/core/support/log.c \
@@ -1299,6 +1310,11 @@
 objs/$(CONFIG)/src/core/support/cmdline.o: 
 objs/$(CONFIG)/src/core/support/cpu_linux.o: 
 objs/$(CONFIG)/src/core/support/cpu_posix.o: 
+objs/$(CONFIG)/src/core/support/env_posix.o: 
+objs/$(CONFIG)/src/core/support/env_win32.o: 
+objs/$(CONFIG)/src/core/support/file.o: 
+objs/$(CONFIG)/src/core/support/file_posix.o: 
+objs/$(CONFIG)/src/core/support/file_win32.o: 
 objs/$(CONFIG)/src/core/support/histogram.o: 
 objs/$(CONFIG)/src/core/support/host_port.o: 
 objs/$(CONFIG)/src/core/support/log.o: 
@@ -4230,6 +4246,68 @@
 endif
 
 
+GPR_FILE_TEST_SRC = \
+    test/core/support/file_test.c \
+
+GPR_FILE_TEST_OBJS = $(addprefix objs/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_FILE_TEST_SRC))))
+
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL with ALPN.
+
+bins/$(CONFIG)/gpr_file_test: openssl_dep_error
+
+else
+
+bins/$(CONFIG)/gpr_file_test: $(GPR_FILE_TEST_OBJS) libs/$(CONFIG)/libgpr_test_util.a libs/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(GPR_FILE_TEST_OBJS) libs/$(CONFIG)/libgpr_test_util.a libs/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o bins/$(CONFIG)/gpr_file_test
+
+endif
+
+objs/$(CONFIG)/test/core/support/file_test.o:  libs/$(CONFIG)/libgpr_test_util.a libs/$(CONFIG)/libgpr.a
+
+deps_gpr_file_test: $(GPR_FILE_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(GPR_FILE_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
+GPR_ENV_TEST_SRC = \
+    test/core/support/env_test.c \
+
+GPR_ENV_TEST_OBJS = $(addprefix objs/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_ENV_TEST_SRC))))
+
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL with ALPN.
+
+bins/$(CONFIG)/gpr_env_test: openssl_dep_error
+
+else
+
+bins/$(CONFIG)/gpr_env_test: $(GPR_ENV_TEST_OBJS) libs/$(CONFIG)/libgpr_test_util.a libs/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(GPR_ENV_TEST_OBJS) libs/$(CONFIG)/libgpr_test_util.a libs/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o bins/$(CONFIG)/gpr_env_test
+
+endif
+
+objs/$(CONFIG)/test/core/support/env_test.o:  libs/$(CONFIG)/libgpr_test_util.a libs/$(CONFIG)/libgpr.a
+
+deps_gpr_env_test: $(GPR_ENV_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(GPR_ENV_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 GPR_SLICE_BUFFER_TEST_SRC = \
     test/core/support/slice_buffer_test.c \