Land #8406, add compatibility shims for older Ruby versions

Gemfile.lock

@@ -28,6 +28,7 @@ PATH
       actionpack (~> 4.2.6)
       activerecord (~> 4.2.6)
       activesupport (~> 4.2.6)
+      backports
       bcrypt
       bit-struct
       filesize
@@ -126,6 +127,7 @@ GEM
       ffi (~> 1.9.10)
       rspec-expectations (>= 2.99)
       thor (~> 0.19)
+    backports (3.8.0)
     bcrypt (3.1.11)
     bindata (2.4.0)
     builder (3.2.3)

lib/msf/core.rb

@@ -12,6 +12,7 @@
 
 # Sanity check this version of ruby
 require 'msf/sanity'
+require 'backports'
 
 # The framework-core depends on Rex
 require 'rex'

metasploit-framework.gemspec

@@ -47,6 +47,8 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency 'activesupport', *Metasploit::Framework::RailsVersionConstraint::RAILS_VERSION
   # Needed for config.action_view for view plugin compatibility for Pro
   spec.add_runtime_dependency 'actionpack', *Metasploit::Framework::RailsVersionConstraint::RAILS_VERSION
+  # Backports Ruby features across language versions
+  spec.add_runtime_dependency 'backports'
   # Needed for some admin modules (cfme_manageiq_evm_pass_reset.rb)
   spec.add_runtime_dependency 'bcrypt'
   # Needed for Javascript obfuscation