[rubygems/rubygems] normalise manifest path from cargo on windows

https://github.com/rubygems/rubygems/commit/23b5ca5fc4

lib/rubygems/ext/cargo_builder.rb

@@ -224,7 +224,7 @@ class Gem::Ext::CargoBuilder < Gem::Ext::Builder
     # --format-version 1 option the output is compatible with YAML, so we can
     # avoid the json dependency
     metadata = Gem::SafeYAML.safe_load(output)
-    package = metadata["packages"].find {|pkg| pkg["manifest_path"] == manifest_path }
+    package = metadata["packages"].find {|pkg| normalize_path(pkg["manifest_path"]) == manifest_path }
     unless package
       found = metadata["packages"].map {|md| "#{md["name"]} at #{md["manifest_path"]}" }
       raise Gem::InstallError, <<-EOF
@@ -239,6 +239,12 @@ EOF
     package["name"].tr("-", "_")
   end
 
+  def normalize_path(path)
+    return path unless File::ALT_SEPARATOR
+
+    path.tr(File::ALT_SEPARATOR, File::SEPARATOR)
+  end
+
   def rustc_dynamic_linker_flags(dest_dir, crate_name)
     split_flags("DLDFLAGS")
       .map {|arg| maybe_resolve_ldflag_variable(arg, dest_dir, crate_name) }