[source] rules.mk: add STAGING_DIR_HOSTPKG variable

[LEDE Commits]

jow pushed a commit to source.git, branch master:
https://git.lede-project.org/d7bec5609c6e7408726f455c97d82b2b99d9ef19

commit d7bec5609c6e7408726f455c97d82b2b99d9ef19
Author: Jo-Philipp Wich <jo at mein.io>
AuthorDate: Tue Nov 1 12:07:56 2016 +0100

    rules.mk: add STAGING_DIR_HOSTPKG variable
    
    Add a STAGING_DIR_HOSTPKG variable which refers to $(STAGING_DIR)/host in order
    to prepare support for relocating that directory in the future.
    
    Signed-off-by: Jo-Philipp Wich <jo at mein.io>
---
 rules.mk | 1 +
 1 file changed, 1 insertion(+)

diff --git a/rules.mk b/rules.mk
index de24778..d455f0d 100644
--- a/rules.mk
+++ b/rules.mk
@@ -140,6 +140,7 @@ PKG_INFO_DIR := $(STAGING_DIR)/pkginfo
 
 BUILD_DIR_HOST:=$(if $(IS_PACKAGE_BUILD),$(BUILD_DIR)/host,$(BUILD_DIR_BASE)/host)
 STAGING_DIR_HOST:=$(TOPDIR)/staging_dir/host
+STAGING_DIR_HOSTPKG:=$(STAGING_DIR)/host
 
 TARGET_PATH:=$(subst $(space),:,$(filter-out .,$(filter-out ./,$(subst :,$(space),$(PATH)))))
 TARGET_INIT_PATH:=$(call qstrip,$(CONFIG_TARGET_INIT_PATH))