Still a lot of bugs to fix, but it is a major step!

214 tests, 378 assertions, 37 failures, 147 errors, 0 pendings, 0 omissions, 0 notifications
14.0187% passed

214 tests, 134243 assertions, 30 failures, 144 errors, 0 pendings, 0 omissions, 0 notifications
18.6916% passed

214 tests, 124651 assertions, 53 failures, 70 errors, 0 pendings, 0 omissions, 0 notifications
42.5234% passed

214 tests, 202091 assertions, 41 failures, 23 errors, 0 pendings, 0 omissions, 0 notifications
70.0935% passed

214 tests, 322331 assertions, 30 failures, 9 errors, 0 pendings, 0 omissions, 0 notifications
81.7757% passed

Unfortunately there is also a sporadic bug/segfault hanging around
that appears to be GC-related.

214 tests, 349898 assertions, 15 failures, 1 errors, 0 pendings, 0 omissions, 0 notifications
92.5234% passed

214 tests, 369388 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed

1. Removed a bunch of internal-only symbols from headers.
2. Required a frozen check to get a non-const pointer to a map or array.
3. De-duplicated the code to get a type argument for Map/RepeatedField.

…assert failure.

Intermittent failure:

ruby: ../../../../ext/google/protobuf_c/protobuf.c:263: ObjectCache_Add: Assertion `rb_funcall(obj_cache2, (__builtin_constant_p("[]") ? __extension__ ({ static ID rb_intern_id_cache; if (!rb_intern_id_cache) rb_intern_id_cache = rb_intern2((("[]")
), (long)strlen(("[]"))); (ID) rb_intern_id_cache; }) : rb_intern("[]")), 1, key_rb) == val' failed

Conformance results now look like:

RUBYLIB=../ruby/lib:. ./conformance-test-runner --enforce_recommended --failure_list failure_list_ruby.txt --text_format_failure_list text_format_failure_list_ruby.txt ./conformance_ruby.rb

CONFORMANCE TEST BEGIN ====================================

CONFORMANCE SUITE PASSED: 1955 successes, 0 skipped, 58 expected failures, 0 unexpected failures.

CONFORMANCE TEST BEGIN ====================================

CONFORMANCE SUITE PASSED: 0 successes, 111 skipped, 8 expected failures, 0 unexpected failures.

Fixes include:

- Changed Ruby compiler to no longer reject proto2 maps.
- Changed Ruby compiler to emit a warning when proto2 extensions are
  present instead of rejecting the .proto file completely.
- Fixed conformance tests to allow proto2 and look up message by name
  instead of hardcoding a specific list of messages.
- Fixed conformance test to support the "ignore unknown" option for
  JSON.
- Fixed conformance test to properly report serialization errors.

…=2.7.