.for f in b.c main.c run.c
${f}: ${AWKSRC}/${f} ${.CURDIR}/${f}.diff
patch -s -b .orig -o ${.TARGET} < ${.CURDIR}/${f}.diff ${AWKSRC}/${f}
SIMPLE_BACKUP_SUFFIX='.orig' patch -s -o ${.TARGET} < ${.CURDIR}/${f}.diff ${AWKSRC}/${f}
CLEANFILES+= ${f}
.endfor