Make USE_NINJA=true the default
Build with kati + ninja by default, unless specifically disabled with
USE_NINJA=false in the environment or on the make command line.
Bug: 23565895
Change-Id: I1fa9f5c6eb4d4ed3f5b81454f89d19fd2f1f6abb
diff --git a/core/main.mk b/core/main.mk
index 6baf6c4..f860f54 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -92,7 +92,7 @@
# and host information.
include $(BUILD_SYSTEM)/config.mk
-ifeq ($(USE_NINJA),true)
+ifneq ($(USE_NINJA),false)
# Mark this is a ninja build.
$(shell mkdir -p $(OUT_DIR) && touch $(OUT_DIR)/ninja_build)
include build/core/ninja.mk