Merge pull request #5182 from...

Merge pull request #5182 from shuujii/use-local-variables-instead-of-top-level-constants-in-boxing.rb

Use local variables instead of top level constants in `boxing.rb` [ci skip]

build_config/boxing.rb

-BOXINGS = %w[no word nan]
-BITS = [64, 32]
-INTS = [64, 32]
+boxings = %w[no word nan]
+bits = [64, 32]
+ints = [64, 32]
 
-BOXINGS.product(BITS, INTS) do |boxing, bit, int|
+boxings.product(bits, ints) do |boxing, bit, int|
   next if boxing == "nan" && int == 64
 
   MRuby::Build.new("boxing-#{boxing}-m#{bit}-i#{int}") do |conf|