Export PRODUCT_SOONG_NAMESPACES to Soong

Bug: 65683273
Test: put 'PRODUCT_SOONG_NAMESPACES := jeff-test/dir1' \
      in a .mk file and observe its value copied into \
      out/soong/soong.variables

Change-Id: I2b61caa46f40f35ccecf64da88918b73180e02e8
diff --git a/core/product.mk b/core/product.mk
index c01a856..f15f6b3 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -102,6 +102,7 @@
     PRODUCT_SDK_ADDON_COPY_MODULES \
     PRODUCT_SDK_ADDON_DOC_MODULES \
     PRODUCT_SDK_ADDON_SYS_IMG_SOURCE_PROP \
+    PRODUCT_SOONG_NAMESPACES \
     PRODUCT_DEFAULT_WIFI_CHANNELS \
     PRODUCT_DEFAULT_DEV_CERTIFICATE \
     PRODUCT_RESTRICT_VENDOR_FILES \
diff --git a/core/product_config.mk b/core/product_config.mk
index 4e2d5ae..5b0e257 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -480,3 +480,7 @@
 # Whether any paths should have CFI enabled for components
 PRODUCT_CFI_INCLUDE_PATHS := \
     $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_CFI_INCLUDE_PATHS))
+
+# which Soong namespaces to export to Make
+PRODUCT_SOONG_NAMESPACES :=
+    $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SOONG_NAMESPACES))
diff --git a/core/soong_config.mk b/core/soong_config.mk
index a90e5af..6f5ca4e 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -121,6 +121,8 @@
 
 $(call add_json_str,  DistDir,                           $(if $(dist_goal), $(DIST_DIR)))
 
+$(call add_json_list, NamespacesToExport,                $(PRODUCT_SOONG_NAMESPACES))
+
 _contents := $(subst $(comma)$(newline)__SV_END,$(newline)}$(newline),$(_contents)__SV_END)
 
 $(file >$(SOONG_VARIABLES).tmp,$(_contents))