LOCAL_HOST_REQUIRED_MODULES support

Allows target modules to directly request host modules they
require to be built and installed as well.

Bug: 72761631
Test: Added LOCAL_HOST_REQUIRED_MODULES to a target apk test and
      the host module was built.

Change-Id: I5aca11b3ba8b54676f068d337f1c9ba0e0b01997
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index 7d3fa75..05e0d8e 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -98,6 +98,7 @@
 LOCAL_GTEST:=true
 LOCAL_HAL_STATIC_LIBRARIES:=
 LOCAL_HEADER_LIBRARIES:=
+LOCAL_HOST_REQUIRED_MODULES:=
 LOCAL_INIT_RC:=
 LOCAL_INSTALLED_MODULE:=
 LOCAL_INSTALLED_MODULE_STEM:=