diff --git a/xorg-x11-server.spec b/xorg-x11-server.spec
index 40a8d04..e02f205 100644
--- a/xorg-x11-server.spec
+++ b/xorg-x11-server.spec
@@ -111,7 +111,7 @@ BuildRequires: libXi-devel libXpm-devel libXaw-devel libXfixes-devel
 BuildRequires: libXv-devel
 
 # openssl? really?
-BuildRequires: pixman-devel libpciaccess-devel openssl-devel byacc
+BuildRequires: pixman-devel libpciaccess-devel openssl-devel byacc flex
 BuildRequires: mesa-libGL-devel >= 7.1
 BuildRequires: mesa-source >= 7.1
 # XXX silly...