build: fix HOST_CONFIGURE_VARS placement

Ensure that HOST_CONFIGURE_VARS are set before the actual configure command
instead of passing them as configure command arguments.

This change brings host-build.mk in line with package-defaults.mk and makes
host configure environment variables work as expected.

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

include/host-build.mk

@@ -80,9 +80,9 @@ define Host/Configure/Default
 	$(if $(HOST_CONFIGURE_PARALLEL),+)(cd $(HOST_BUILD_DIR)/$(3); \
 		if [ -x configure ]; then \
 			$(CP) $(SCRIPT_DIR)/config.{guess,sub} $(HOST_BUILD_DIR)/$(3)/ && \
+			$(HOST_CONFIGURE_VARS) \
 			$(2) \
 			$(HOST_CONFIGURE_CMD) \
-			$(HOST_CONFIGURE_VARS) \
 			$(HOST_CONFIGURE_ARGS) \
 			$(1); \
 		fi \