diff --git a/contrib/thrift.spec b/contrib/thrift.spec
index 4197390..93f000c 100644
--- a/contrib/thrift.spec
+++ b/contrib/thrift.spec
@@ -163,6 +163,7 @@
 %setup -q
 
 %build
+[[ -e Makefile.in ]] || ./bootstrap.sh
 export GEM_HOME=${PWD}/.gem-home
 export RUBYLIB=${PWD}/lib/rb/lib
 %configure \