(CRT1_DIR): Set to ${crt1_dir}/ if crt1_dir is non-empty.
* Makefile.am: Change all occurrences of $(CRT0_DIR)/$(CRT0) to
$(CRT0_DIR)$(CRT0) to prevent make warnings. Likewise for
$(CRT1_DIR)/$(CRT1).
* libc/machine/xstormy16/Makefile.in: Regenerated.
* libc/machine/xstormy16/aclocal.m4: Regenerated.
* libc/machine/xstormy16/configure: Regenerated.