Prevent ffi and childprocess causing build failures (#2595)

Gemfile

@@ -32,16 +32,29 @@ if RUBY_VERSION < '2.0.0' || RUBY_ENGINE == 'java'
   gem 'json', '< 2.0.0'
 end
 
-if RUBY_VERSION < '2.0.0' && !!(RbConfig::CONFIG['host_os'] =~ /cygwin|mswin|mingw|bccwin|wince|emx/)
+if RUBY_VERSION < '2.2.0' && !!(RbConfig::CONFIG['host_os'] =~ /cygwin|mswin|mingw|bccwin|wince|emx/)
+  gem 'ffi', '< 1.10'
+elsif RUBY_VERSION < '2.0.0' && !!(RbConfig::CONFIG['host_os'] =~ /cygwin|mswin|mingw|bccwin|wince|emx/)
   gem 'ffi', '< 1.9.15' # allow ffi to be installed on older rubies on windows
 elsif RUBY_VERSION < '1.9'
   gem 'ffi', '< 1.9.19' # ffi dropped Ruby 1.8 support in 1.9.19
 else
   gem 'ffi', '~> 1.9.25'
 end
 
+if RUBY_VERSION < '2.2.0' && !!(RbConfig::CONFIG['host_os'] =~ /cygwin|mswin|mingw|bccwin|wince|emx/)
+  gem "childprocess", "< 1.0.0"
+end
+
 platforms :jruby do
-  gem "jruby-openssl"
+  if RUBY_VERSION < '1.9.0'
+    # Pin jruby-openssl on older J Ruby
+    gem "jruby-openssl", "< 0.10.0"
+    # Pin child-process on older J Ruby
+    gem "childprocess", "< 1.0.0"
+  else
+    gem "jruby-openssl"
+  end
 end
 
 gem 'simplecov', '~> 0.8'