in ARCH, there are all -m flags (will be expanded into ARCH_FLAGS in Makefile)
in DEFS, there are all -D flags (will be expanded into DEFS in Makefile)
in LIB, there are all -l flags (will be expanded into LIBNAME in Makefile)
If no MODE option specified, the generator behaves as in previous version.
This makes possibility for the script to append the definitions to CFLAGS
and LDFLAGS, and with the feature of disabling of -D prependation it will
make possible to generate ARCH_FLAGS generic to each specific chip.
