# merge libs into a single static library
function(merge_static_libs outlib )
	set(libs ${ARGV})
	list(REMOVE_AT libs 0)

	set(objdir ${CMAKE_CURRENT_BINARY_DIR}/tmpobj)
	file(MAKE_DIRECTORY ${objdir})

	set(dummyfile ${CMAKE_CURRENT_BINARY_DIR}/${outlib}_dummy.c)
	if(NOT EXISTS ${dummyfile})
		file(WRITE ${dummyfile} "const char *dummy = \"${dummyfile}\";")
	endif()
	set_source_files_properties("${dummyfile}" PROPERTIES COMPILE_FLAGS -Wno-missing-variable-declarations)
	add_library(${outlib} STATIC ${dummyfile})

	set(outfile $<TARGET_FILE:${outlib}>)

	foreach(lib ${libs})
		add_custom_command(TARGET ${outlib} POST_BUILD
				DEPENDS ${lib}
				COMMAND ${CMAKE_COMMAND} -E echo "AR x ${lib}"
				COMMAND ${CMAKE_AR} x $<TARGET_FILE:${lib}>
				WORKING_DIRECTORY ${objdir})
	endforeach()
	add_custom_command(TARGET ${outlib} POST_BUILD
			DEPENDS ${lib}
			COMMAND ${CMAKE_COMMAND} -E echo "AR ru ${outlib} tmpobj/*.o"
			COMMAND ${CMAKE_AR} ru "${outfile}" "${objdir}/*.o"
			WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})

endfunction()