soong: add TARGET_SPECIFIC_HEADER_PATH

Change-Id: I582ae8e6e010016b33fd9b020b723e5fc2dc442b
diff --git a/build/soong/android/variable.go b/build/soong/android/variable.go
index 04aa4f5..d06c924 100644
--- a/build/soong/android/variable.go
+++ b/build/soong/android/variable.go
@@ -86,6 +86,7 @@
 	Target_needs_netd_direct_connect_rule  *bool `json:",omitempty"`
 	Target_process_sdk_version_override  *string `json:",omitempty"`
 	Target_shim_libs  *string `json:",omitempty"`
+	Target_specific_header_path  *string `json:",omitempty"`
 	Target_surfaceflinger_fod_lib  *string `json:",omitempty"`
 	Uses_generic_camera_parameter_library  *bool `json:",omitempty"`
 	Uses_nvidia_enhancements  *bool `json:",omitempty"`