+diff -u -r ../ruby-2.3.0/tool/rbinstall.rb ./tool/rbinstall.rb
+--- ../ruby-2.3.0/tool/rbinstall.rb 2015-11-16 01:33:17.000000000 -0500
++++ ./tool/rbinstall.rb 2015-12-25 15:43:04.756646343 -0500
+@@ -696,7 +696,7 @@
+ # :startdoc:
+
+ install?(:ext, :comm, :gem) do
+- gem_dir = Gem.default_dir
++ gem_dir = "@TERMUX_PREFIX@/lib/ruby/gems/2.4.0"
+ directories = Gem.ensure_gem_subdirectories(gem_dir, :mode => $dir_mode)
+ prepare "default gems", gem_dir, directories
+
+@@ -732,7 +732,7 @@
+ end
+
+ install?(:ext, :comm, :gem) do
+- gem_dir = Gem.default_dir
++ gem_dir = "@TERMUX_PREFIX@/lib/ruby/gems/2.4.0"
+ directories = Gem.ensure_gem_subdirectories(gem_dir, :mode => $dir_mode)
+ prepare "bundle gems", gem_dir, directories
+ install_dir = with_destdir(gem_dir)