gallium: always build drivers/sw
diff --git a/SConstruct b/SConstruct
index 1c8a00c..76ada41 100644
--- a/SConstruct
+++ b/SConstruct
@@ -136,6 +136,8 @@
     env['drivers'].append('softpipe')
 if env['llvm'] and 'llvmpipe' not in env['drivers']:
     env['drivers'].append('llvmpipe')
+if 'sw' not in env['drivers']:
+    env['drivers'].append('sw')
 
 # Includes
 env.Prepend(CPPPATH = [