Attemt to fix BlankSlate for Ruby 3.0 compatibility.

Resolves: rhbz#1923688

rubygem-builder-3.2.4-Fix-Ruby-3-compatibility.patch

@@ -0,0 +1,13 @@
+diff --git a/lib/blankslate.rb b/lib/blankslate.rb
+index 7ea1864..b974f40 100644
+--- a/lib/blankslate.rb
++++ b/lib/blankslate.rb
+@@ -129,7 +129,7 @@ class Module
+   alias blankslate_original_append_features append_features
+   def append_features(mod)
+     result = blankslate_original_append_features(mod)
+-    return result if mod != Object
++    return result if (mod != Object && mod != Kernel)
+     instance_methods.each do |name|
+       BlankSlate.hide(name)
+     end

rubygem-builder.spec

@@ -2,11 +2,14 @@
 
 Name: rubygem-%{gem_name}
 Version: 3.2.4
-Release: 3%{?dist}
+Release: 4%{?dist}
 Summary: Builders for MarkUp
 License: MIT
 URL: http://onestepback.org
 Source0: https://rubygems.org/gems/%{gem_name}-%{version}.gem
+# Attemt to fix BlankSlate for Ruby 3.0 compatibility.
+# https://github.com/tenderlove/builder/issues/13
+Patch0: rubygem-builder-3.2.4-Fix-Ruby-3-compatibility.patch
 # Builder carries copy of Blankslate, which was in the meantime extracted into
 # independent gem.
 # https://github.com/jimweirich/builder/issues/24
@@ -39,6 +42,8 @@ Documentation for %{name}.
 %prep
 %setup -q -n %{gem_name}-%{version}
 
+%patch0 -p1
+
 %build
 # Create the gem as gem install only works on a gem file
 gem build ../%{gem_name}-%{version}.gemspec
@@ -85,6 +90,10 @@ popd
 %{gem_instdir}/test
 
 %changelog
+* Tue Mar 16 2021 Vít Ondruch <vondruch@redhat.com> - 3.2.4-4
+- Attemt to fix BlankSlate for Ruby 3.0 compatibility.
+  Resolves: rhbz#1923688
+
 * Wed Jan 27 2021 Fedora Release Engineering <releng@fedoraproject.org> - 3.2.4-3
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_34_Mass_Rebuild