HHVM blockers for Drupal

hhvmnotes.txt

Blocking Drupal CI (our testbot) working with HHVM:

- Our testbot uses our SQLite driver to store results in a local SQLite database, 
  even if we are testing using MySQL/MariaDB/Postgres. Unfortunately we use the
  unimplemented PDO::sqliteCreateCollation (which is the same as the also-
  unimplemented sqlite3::createCollation) method to set up a userland case-
  insensitive collation. I might be able to hack out a PR for this myself in spite
  of my non-existent C++ though.

- Even if I patch this so the container can run I'm getting weird Reflection errors
  that might point to an HHVM problem, but haven't sussed this out yet.

Blocking performance testing:

- I appear to be able to replicate https://github.com/facebook/hhvm/issues/6296 where
  --hphp builds completely fail. This appears to be broken with oss-performance HEAD
  on HHVM 3.9.1 as well as with my updates for Drupal RC1. This in turns means I can 
  only test with --no-repo-auth which is sad. :(

Blocking Postgres usage:

- We use bytea columns which are broken with PDO. See:
  - https://github.com/PocketRent/hhvm-pgsql/issues/46 and 
  - https://github.com/PocketRent/hhvm-pgsql/issues/77
  Drupal can't install on pgsql without these fixed.