gnulib-tool: Recognize @LT@, @la@, @lo@ tokens in module descriptions. * gnulib-tool.sh (func_emit_lib_Makefile_am): Replace @LT@, @la@, @lo@ tokens. (func_emit_tests_Makefile_am): Likewise. * pygnulib/GLEmiter.py (GLEmiter.lib_Makefile_am): Likewise. (GLEmiter.tests_Makefile_am): Likewise.