diff --git a/Rakefile b/Rakefile
index 8aa4d23..a9fa384 100644
--- a/Rakefile
+++ b/Rakefile
@@ -6,9 +6,9 @@ ENV['MRUBY_VERSION'] ||= 'stable'
 file :mruby do
   case ENV['MRUBY_VERSION']&.downcase
   when 'head', 'master'
-    sh(*%w[git clone --depth 1 git://github.com/mruby/mruby.git])
+    sh(*%w[git clone --depth 1 https://@github.com/mruby/mruby.git])
   when 'stable'
-    sh(*%w[git clone --depth 1 git://github.com/mruby/mruby.git -b stable])
+    sh(*%w[git clone --depth 1 https://@github.com/mruby/mruby.git -b stable])
   else
     sh "curl -L --fail --retry 3 --retry-delay 1 https://github.com/mruby/mruby/archive/#{ENV['MRUBY_VERSION']}.tar.gz -s -o - | tar zxf -" # rubocop:disable Layout/LineLength
     mv "mruby-#{ENV['MRUBY_VERSION']}", 'mruby'
diff --git a/src/mrb_thread.c b/src/mrb_thread.c
index 0c5cdcf..1f7916d 100644
--- a/src/mrb_thread.c
+++ b/src/mrb_thread.c
@@ -25,6 +25,10 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#if MRUBY_RELEASE_NO > 30100
+# include <mruby/internal.h>
+#endif
+
 /*
 For backward compatibility.
 See also https://github.com/mruby/mruby/commit/79a621dd739faf4cc0958e11d6a887331cf79e48