Documentation/Makefile.sphinx: Be cautious when running `rm -rf`

If BUILDDIR were an empty string, running `make clean` would result in
running `rm -rf /*`. Omitting the trailing /* prevents this.

With a valid BUILDDIR, the behaviour of `make clean` changes slightly in
that BUILDDIR itself is removed. However, this is probably more in line
with what one would expect from `make clean`.

Change-Id: I51b52bb6e7fe73a07fed6291a4f1cc253f2bf319
Signed-off-by: Tristan Corrick <>
Reviewed-by: Angel Pons <>
Reviewed-by: Patrick Georgi <>
Reviewed-by: Stefan Tauner <>
Tested-by: build bot (Jenkins) <>
1 file changed