TruffleRuby - GraalVM Community Edition 1.0 RC16

Bug fixes:

• Fixed Hash#merge with no arguments to return a new copy of the receiver (#1645).
• Fixed yield with a splat and keyword arguments (#1613).
• Fixed rb_scan_args to correctly handle kwargs in combination with optional args.
• Many fixes for FFI::Pointer to be more compatible with the ffi gem.

New features:

• Rounding modes have been implemented or improved for Float, Rational, BigDecimal (#1509).
• Support Homebrew installed in other prefixes than /usr/local (#1583).
• Added a pure-Ruby implementation of FFI which passes almost all Ruby FFI specs (#1529, #1524).

Changes:

• Support for the Darkfish theme for RDoc generation has been removed.

Compatibility:

• The KeyError raised from ENV#fetch and Hash#fetch now matches MRI's message formatting (#1633).
• Add the missing key and receiver values to KeyError raised from ENV#fetch.
• String#unicode_normalize has been moved to the core library like in MRI.
• StringScanner will now match a regexp beginning with ^ even when not scanning from the start of the string.
• Module#define_method is now public like in MRI.
• Kernel#warn now supports the uplevel: keyword argument.