Read Soong-exported configuration

This is to ensure that Make and Soong agree on configuration variables
like TARGET_GLOBAL_CFLAGS. Only a few variables are actually checked
currently until we make more actually the same.

Bug: 23566674
Change-Id: Ibede43d933ede4d470e182f9490ea6ec4ef52fbc
diff --git a/core/main.mk b/core/main.mk
index c455320..6401efc 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -107,6 +107,8 @@
 include build/core/ninja.mk
 else # KATI
 
+include $(SOONG_MAKEVARS_MK)
+
 # Write the build number to a file so it can be read back in
 # without changing the command line every time.  Avoids rebuilds
 # when using ninja.
diff --git a/core/ninja.mk b/core/ninja.mk
index 9e78c46..5136f4e 100644
--- a/core/ninja.mk
+++ b/core/ninja.mk
@@ -159,7 +159,7 @@
 endif
 $(KATI_BUILD_NINJA): $(CKATI) $(MAKEPARALLEL) $(DUMMY_OUT_MKS) run_soong FORCE
 	@echo Running kati to generate build$(KATI_NINJA_SUFFIX).ninja...
-	+$(hide) $(KATI_MAKEPARALLEL) $(CKATI) --ninja --ninja_dir=$(OUT_DIR) --ninja_suffix=$(KATI_NINJA_SUFFIX) --regen --ignore_dirty=$(OUT_DIR)/% --no_ignore_dirty=$(SOONG_ANDROID_MK) --ignore_optional_include=$(OUT_DIR)/%.P --detect_android_echo $(KATI_FIND_EMULATOR) -f build/core/main.mk $(KATI_GOALS) --gen_all_targets BUILDING_WITH_NINJA=true SOONG_ANDROID_MK=$(SOONG_ANDROID_MK)
+	+$(hide) $(KATI_MAKEPARALLEL) $(CKATI) --ninja --ninja_dir=$(OUT_DIR) --ninja_suffix=$(KATI_NINJA_SUFFIX) --regen --ignore_dirty=$(OUT_DIR)/% --no_ignore_dirty=$(SOONG_ANDROID_MK) --no_ignore_dirty=$(SOONG_MAKEVARS_MK) --ignore_optional_include=$(OUT_DIR)/%.P --detect_android_echo $(KATI_FIND_EMULATOR) -f build/core/main.mk $(KATI_GOALS) --gen_all_targets BUILDING_WITH_NINJA=true SOONG_ANDROID_MK=$(SOONG_ANDROID_MK) SOONG_MAKEVARS_MK=$(SOONG_MAKEVARS_MK)
 
 .PHONY: FORCE
 FORCE:
diff --git a/core/soong.mk b/core/soong.mk
index df581aa..f1d765c 100644
--- a/core/soong.mk
+++ b/core/soong.mk
@@ -3,6 +3,7 @@
 SOONG_BOOTSTRAP := $(SOONG_OUT_DIR)/.soong.bootstrap
 SOONG_BUILD_NINJA := $(SOONG_OUT_DIR)/build.ninja
 SOONG_IN_MAKE := $(SOONG_OUT_DIR)/.soong.in_make
+SOONG_MAKEVARS_MK := $(SOONG_OUT_DIR)/make_vars-$(TARGET_PRODUCT).mk
 SOONG_VARIABLES := $(SOONG_OUT_DIR)/soong.variables
 
 # Only include the Soong-generated Android.mk if we're merging the