only store files in .oxt, do not compress

Saves build time. Saves startup time. Better compression is
possible when making install sets.

solenv/inc/extension_pre.mk

@@ -52,7 +52,7 @@ ZIP9DEPS=		$(PACKLICS) $(DESCRIPTION) $(COMPONENT_XCU) $(COMPONENT_FILES) $(COMP
 ZIP9TARGET=		$(EXTENSION_ZIPNAME)
 ZIP9DIR=		$(EXTENSIONDIR)
 ZIP9EXT=		.oxt
-ZIP9FLAGS=-r
+ZIP9FLAGS=-0 -r
 ZIP9LIST=		*
 .ENDIF			# "$(COMPONNENT_COPYONLY)"==""