diff --git a/rubygem-cairo.spec b/rubygem-cairo.spec
index 5d5f159..8ad4a5c 100644
--- a/rubygem-cairo.spec
+++ b/rubygem-cairo.spec
@@ -113,7 +113,7 @@ ruby-cairo
 
 mkdir -p ./%{gem_dir}
 export CONFIGURE_ARGS="--with-cflags='%{optflags}'"
-%gem_install
+%gem_install -n %{SOURCE0}
 
 find . -name \*.gem | xargs chmod 0644