soong_config: Allow process-specific override of target SDK version

Change-Id: I775e852c17af12d2233e644e3db10c10bcb20d19
diff --git a/build/soong/android/variable.go b/build/soong/android/variable.go
index 27f1e2e..693f981 100644
--- a/build/soong/android/variable.go
+++ b/build/soong/android/variable.go
@@ -9,6 +9,9 @@
 	Needs_text_relocations struct {
 		Cppflags []string
 	}
+	Target_process_sdk_version_override struct {
+		Cppflags []string
+	}
 	Target_shim_libs struct {
 		Cppflags []string
 	}
@@ -33,6 +36,7 @@
 	Java_Source_Overlays *string `json:",omitempty"`
 	Needs_text_relocations  *bool `json:",omitempty"`
 	Specific_camera_parameter_library  *string `json:",omitempty"`
+	Target_process_sdk_version_override *string `json:",omitempty"`
 	Target_shim_libs  *string `json:",omitempty"`
 	Uses_generic_camera_parameter_library  *bool `json:",omitempty"`
 	Uses_nvidia_enhancements  *bool `json:",omitempty"`
diff --git a/build/soong/soong_config.mk b/build/soong/soong_config.mk
index 852ee84..9ac6b9a 100644
--- a/build/soong/soong_config.mk
+++ b/build/soong/soong_config.mk
@@ -8,6 +8,7 @@
 $(call add_json_str, Java_Source_Overlays, $(JAVA_SOURCE_OVERLAYS))
 $(call add_json_bool, Needs_text_relocations, $(filter true,$(TARGET_NEEDS_PLATFORM_TEXT_RELOCATIONS)))
 $(call add_json_str, Specific_camera_parameter_library, $(TARGET_SPECIFIC_CAMERA_PARAMETER_LIBRARY))
+$(call add_json_str_omitempty, Target_process_sdk_version_override, $(TARGET_PROCESS_SDK_VERSION_OVERRIDE))
 $(call add_json_str, Target_shim_libs, $(TARGET_LD_SHIM_LIBS))
 $(call add_json_bool, Uses_generic_camera_parameter_library, $(if $(TARGET_SPECIFIC_CAMERA_PARAMETER_LIBRARY),,true))
 $(call add_json_bool, Uses_nvidia_enhancements, $(filter TRUE,$(NV_ANDROID_FRAMEWORK_ENHANCEMENTS)))