[rubygems/rubygems] Refactor platform matching on Linux

I think this highlights better how musl is special.

https://github.com/rubygems/rubygems/commit/4075771697

lib/bundler/rubygems_ext.rb

@@ -261,10 +261,21 @@ module Gem
           # version
           (
             (@os != "linux" && (@version.nil? || other.version.nil?)) ||
-            (@os == "linux" && (other.version == "gnu#{@version}" || other.version == "musl#{@version}" || @version == "gnu#{other.version}")) ||
+            (@os == "linux" && (normalized_linux_version_ext == other.normalized_linux_version_ext || other.version == "musl#{@version}")) ||
             @version == other.version
           )
       end
+
+      # This is a copy of RubyGems 3.3.23 or higher `normalized_linux_method`.
+      # Once only 3.3.23 is supported, we can use the method in RubyGems.
+      def normalized_linux_version_ext
+        return nil unless @version
+
+        without_gnu = @version.sub(/\Agnu/, "")
+        return nil if without_gnu.empty?
+
+        without_gnu
+      end
     end
   end
 

lib/rubygems/platform.rb

@@ -181,11 +181,20 @@ class Gem::Platform
       # version
       (
         (@os != "linux" && (@version.nil? || other.version.nil?)) ||
-        (@os == "linux" && (other.version == "gnu#{@version}" || other.version == "musl#{@version}" || @version == "gnu#{other.version}")) ||
+        (@os == "linux" && (normalized_linux_version == other.normalized_linux_version || other.version == "musl#{@version}")) ||
         @version == other.version
       )
   end
 
+  def normalized_linux_version
+    return nil unless @version
+
+    without_gnu = @version.sub(/\Agnu/, "")
+    return nil if without_gnu.empty?
+
+    without_gnu
+  end
+
   ##
   # Does +other+ match this platform?  If +other+ is a String it will be
   # converted to a Gem::Platform first.  See #=== for matching rules.