diff --git a/rubygem-cairo.spec b/rubygem-cairo.spec
index 929b32f..34ceaef 100644
--- a/rubygem-cairo.spec
+++ b/rubygem-cairo.spec
@@ -86,33 +86,19 @@ Header files and libraries for building a extension library for the
 ruby-cairo
 
 %prep
-%setup -q -c -T
-
-TOPDIR=$(pwd)
-mkdir tmpunpackdir
-pushd tmpunpackdir
-
-gem unpack %{SOURCE0}
-cd %{gem_name}-%{version}
+%setup -q -n %{gem_name}-%{version}
+mv ../%{gem_name}-%{version}.gemspec .
 
 #Patches, etc
 
-gem specification -l --ruby %{SOURCE0} > %{gem_name}.gemspec
-
 # pkg-config dependency should be for development
-find . -name \*.gemspec | \
-	xargs sed -i  \
-		-e '\@pkg-config@s|runtime_dependency|development_dependency|' \
-		-e '\@native-package-installer@s|runtime_dependency|development_dependency|' \
-		%{nil}
-
-gem build %{gem_name}.gemspec
-mv %{gem_name}-%{version}.gem $TOPDIR
-
-popd
-rm -rf tmpunpackdir
+sed -i  %{gem_name}-%{version}.gemspec \
+	-e '\@pkg-config@s|runtime_dependency|development_dependency|' \
+	-e '\@native-package-installer@s|runtime_dependency|development_dependency|' \
+	%{nil}
 
 %build
+gem build %{gem_name}-%{version}.gemspec
 %gem_install
 
 # Once install to TMPINSTDIR for %%check