scons: Always load lex/yacc tool.

lex/yacc is not loaded by default when toolchain is not default either,
e.g., when toolchain=crossmingw.

diff --git a/scons/gallium.py b/scons/gallium.py
index 112f6c8..34523d5 100755 (executable)
--- a/scons/gallium.py
+++ b/scons/gallium.py
@@ -598,6 +598,8 @@ def generate(env):
     env.Append(LIBS = [])
 
     # Load tools
+    env.Tool('lex')
+    env.Tool('yacc')
     if env['llvm']:
         env.Tool('llvm')
         env.Tool('udis86')