diff --git a/configure.ac b/configure.ac
index 6a5bb37..7737273 100644
--- a/configure.ac
+++ b/configure.ac
@@ -617,6 +617,13 @@
     [with_gallium_drivers="$withval"],
     [with_gallium_drivers="$GALLIUM_DRIVERS_DEFAULT"])
 
+# Doing '--without-gallium-drivers' will set this variable to 'no'.  Clear it
+# here so that the script doesn't choke on an unknown driver name later.
+case "$with_gallium_drivers" in
+    yes) with_gallium_drivers="$GALLIUM_DRIVERS_DEFAULT" ;;
+    no) with_gallium_drivers='' ;;
+esac
+
 if test "x$enable_opengl" = xno -a \
         "x$enable_gles1" = xno -a \
         "x$enable_gles2" = xno -a \