build: fix triggering opkg/host compilation

Commit 131db366 "build: remove separate /install step for host builds" dropped
the package/*/host/install targets in favor to performing the install steps
within the compile target instead.

Adjust package/Makefile accordingly in order to prevent a missing
staging_dir/host/bin/opkg when staging package archives into the rootfs.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

package/Makefile

@@ -57,7 +57,7 @@ $(curdir)/merge:
 $(curdir)/merge-index: $(curdir)/merge
 	(cd $(PACKAGE_DIR_ALL) && $(SCRIPT_DIR)/ipkg-make-index.sh . 2>&1 > Packages; )
 
-$(curdir)/install: $(TMP_DIR)/.build $(curdir)/system/opkg/host/install $(curdir)/merge $(if $(CONFIG_TARGET_PER_DEVICE_ROOTFS),$(curdir)/merge-index)
+$(curdir)/install: $(TMP_DIR)/.build $(curdir)/system/opkg/host/compile $(curdir)/merge $(if $(CONFIG_TARGET_PER_DEVICE_ROOTFS),$(curdir)/merge-index)
 	- find $(STAGING_DIR_ROOT) -type d | $(XARGS) chmod 0755
 	rm -rf $(TARGET_DIR) $(TARGET_DIR_ORIG)
 	[ -d $(TARGET_DIR)/tmp ] || mkdir -p $(TARGET_DIR)/tmp