it to foo.h. This was causing problems with:
.y.h: ${.TARGET:.h=.c}
where .h was ./cgram.h and the source became ./cgram.c confusing for example
/usr/src/tools/lint1 because make had both cgram.c and ./cgram.c in the list
of sources, trying to build both of them in parallel thinking that they were
different files. Since the regular mkdep does not produce such dependencies,
the regular build does not suffer from this issue.