diff --git a/rubygem-backports.spec b/rubygem-backports.spec
index aafd89c..7a6a8a0 100644
--- a/rubygem-backports.spec
+++ b/rubygem-backports.spec
@@ -34,12 +34,16 @@ BuildArch: noarch
 Documentation for %{name}.
 
 %prep
-%setup -q -c -T
-mkdir -p .%{gem_dir}
-gem install --local --install-dir .%{gem_dir} \
-            --force %{SOURCE0}
+gem unpack %{SOURCE0}
+
+%setup -q -D -T -n  %{gem_name}-%{version}
+
+gem spec %{SOURCE0} -l --ruby > %{gem_name}.gemspec
 
 %build
+gem build %{gem_name}.gemspec
+
+%gem_install
 
 %install
 mkdir -p %{buildroot}%{gem_dir}