Build an intermediate object file even when there is only one source
file. This costs a little space but saves time if the target is rebuilt
a lot, and it stops the target varying with the name of temporary
intermediates.
Use ${ECHO} instead of `echo' so that `make -s' is fairly quiet.
Use ${ECHODIR} instead of echo for printing directory names so that
`make -ss' is very quiet.
a4c39c7aa6