diff --git a/core/config.mk b/core/config.mk
index dd0dfc2d8d..a7517f3795 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -120,8 +120,8 @@ hide := $(if $(SHOW_COMMANDS),,@)
 COMMON_GLOBAL_CFLAGS:= -DANDROID -fmessage-length=0 -W -Wall -Wno-unused -Winit-self -Wpointer-arith
 COMMON_RELEASE_CFLAGS:= -DNDEBUG -UDEBUG
 
-COMMON_GLOBAL_CPPFLAGS:= $(COMMON_GLOBAL_CFLAGS) -Wsign-promo
-COMMON_RELEASE_CPPFLAGS:= $(COMMON_RELEASE_CFLAGS)
+COMMON_GLOBAL_CPPFLAGS:= -Wsign-promo
+COMMON_RELEASE_CPPFLAGS:=
 
 GLOBAL_CFLAGS_NO_OVERRIDE := \
     -Werror=int-to-pointer-cast \
@@ -181,7 +181,6 @@ BUILD_DATETIME_C_TIME := $$(cat $(OUT_DIR)/build_c_time.txt)
 
 ifeq ($(OVERRIDE_C_DATE_TIME),true)
 COMMON_GLOBAL_CFLAGS += -Wno-builtin-macro-redefined -D__DATE__="\"$(BUILD_DATETIME_C_DATE)\"" -D__TIME__=\"$(BUILD_DATETIME_C_TIME)\"
-COMMON_GLOBAL_CPPFLAGS += -Wno-builtin-macro-redefined -D__DATE__="\"$(BUILD_DATETIME_C_DATE)\"" -D__TIME__=\"$(BUILD_DATETIME_C_TIME)\"
 endif
 
 # The build system exposes several variables for where to find the kernel
@@ -582,7 +581,6 @@ TARGET_PROJECT_INCLUDES:= $(SRC_HEADERS) $(TARGET_OUT_HEADERS) \
 # sure to only specify them for the target compilers checked in to
 # the source tree.
 TARGET_GLOBAL_CFLAGS += $(TARGET_ERROR_FLAGS)
-TARGET_GLOBAL_CPPFLAGS += $(TARGET_ERROR_FLAGS)
 
 HOST_GLOBAL_CFLAGS += $(HOST_RELEASE_CFLAGS)
 HOST_GLOBAL_CPPFLAGS += $(HOST_RELEASE_CPPFLAGS)
@@ -598,7 +596,6 @@ $(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_RELEASE_CPPFLAGS += $(COMMON_RELEASE_CPPFLAG
 $(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_LD_DIRS += -L$($(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_OUT_INTERMEDIATE_LIBRARIES)
 $(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_PROJECT_INCLUDES := $(TARGET_PROJECT_INCLUDES)
 $(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_CFLAGS += $(TARGET_ERROR_FLAGS)
-$(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_CPPFLAGS += $(TARGET_ERROR_FLAGS)
 $(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_CFLAGS += $($(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_RELEASE_CFLAGS)
 $(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_CPPFLAGS += $($(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_RELEASE_CPPFLAGS)
 endif
diff --git a/core/ninja.mk b/core/ninja.mk
index 2aa0b283ae..c469e02119 100644
--- a/core/ninja.mk
+++ b/core/ninja.mk
@@ -135,7 +135,7 @@ kati.intermediate: $(KATI) $(MAKEPARALLEL)
 	@echo Running kati to generate build$(KATI_NINJA_SUFFIX).ninja...
 	+$(hide) $(KATI_MAKEPARALLEL) $(KATI) --ninja --ninja_dir=$(PRODUCT_OUT) --ninja_suffix=$(KATI_NINJA_SUFFIX) --regen --ignore_dirty=$(OUT_DIR)/% --ignore_optional_include=$(OUT_DIR)/%.P --detect_android_echo --use_find_emulator $(KATI_REMOTE_NUM_JOBS_FLAG) -f build/core/main.mk $(or $(KATI_TARGETS),--gen_all_phony_targets) USE_NINJA=false
 
-KATI_CXX := $(CLANG_CXX) $(CLANG_HOST_GLOBAL_CPPFLAGS)
+KATI_CXX := $(CLANG_CXX) $(CLANG_HOST_GLOBAL_CFLAGS) $(CLANG_HOST_GLOBAL_CPPFLAGS)
 KATI_LD := $(CLANG_CXX) $(CLANG_HOST_GLOBAL_LDFLAGS)
 # Build static ckati. Unfortunately Mac OS X doesn't officially support static exectuables.
 ifeq ($(BUILD_OS),linux)