diff --git a/core/ninja.mk b/core/ninja.mk
index 8a94f39..9e78c46 100644
--- a/core/ninja.mk
+++ b/core/ninja.mk
@@ -104,13 +104,15 @@
 NINJA_STATUS := [%p %s/%t]$(space)
 endif
 
+NINJA_EXTRA_ARGS :=
+
 ifneq (,$(filter showcommands,$(ORIGINAL_MAKECMDGOALS)))
-NINJA_ARGS += "-v"
+NINJA_EXTRA_ARGS += "-v"
 endif
 
 # Make multiple rules to generate the same target an error instead of
 # proceeding with undefined behavior.
-NINJA_ARGS += -w dupbuild=err
+NINJA_EXTRA_ARGS += -w dupbuild=err
 
 ifdef USE_GOMA
 KATI_MAKEPARALLEL := $(MAKEPARALLEL)
@@ -118,11 +120,13 @@
 # this parallelism. Note the parallelism of all other jobs is still
 # limited by the -j flag passed to GNU make.
 NINJA_REMOTE_NUM_JOBS ?= 500
-NINJA_ARGS += -j$(NINJA_REMOTE_NUM_JOBS)
+NINJA_EXTRA_ARGS += -j$(NINJA_REMOTE_NUM_JOBS)
 else
 NINJA_MAKEPARALLEL := $(MAKEPARALLEL) --ninja
 endif
 
+NINJA_ARGS += $(NINJA_EXTRA_ARGS)
+
 ifeq ($(USE_SOONG),true)
 COMBINED_BUILD_NINJA := $(OUT_DIR)/combined$(KATI_NINJA_SUFFIX).ninja
 
diff --git a/core/soong.mk b/core/soong.mk
index 3450695..990a861 100644
--- a/core/soong.mk
+++ b/core/soong.mk
@@ -79,4 +79,4 @@
 # prebuilts.
 .PHONY: run_soong
 run_soong: $(SOONG_BOOTSTRAP) $(SOONG_VARIABLES) $(SOONG_IN_MAKE) FORCE
-	$(hide) $(SOONG) $(SOONG_BUILD_NINJA) $(NINJA_ARGS)
+	$(hide) $(SOONG) $(SOONG_BUILD_NINJA) $(NINJA_EXTRA_ARGS)