Fix Makefile for toolchain_build_pnacl.py.

BUG=None
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/923183002
diff --git a/Makefile b/Makefile
index 49161dd..2e92992 100644
--- a/Makefile
+++ b/Makefile
@@ -15,5 +15,6 @@
 CXX.Flags += -std=c++11
 
 CPP.Defines += -DALLOW_DUMP=1 -DALLOW_LLVM_CL=1 -DALLOW_LLVM_IR=1 \
-	-DALLOW_LLVM_IR_AS_INPUT=1 -DALLOW_DISABLE_IR_GEN=1
+	-DALLOW_LLVM_IR_AS_INPUT=1 -DALLOW_DISABLE_IR_GEN=1 \
+	-DALLOW_MINIMAL_BUILD=0