adding a directory on a branch

[DJ Delorie]

> toplevel
> '-- libbackend

Please do not encourage such vague names for toplevel directories.
Remember, many people merge the gcc toplevel with other projects
(binutils, gdb, newlib, cygwin, etc) and having a toplevel directory
that isn't named in an obvious and clear manner would be very
confusing.

In the example above, it's also bad to be calling a HOST library
"libfoo" as most of the other "libfoo" are target libraries (yes,
libcpp is an exception.  Sigh).  I'd call it "gccbackend" (or "gccbe"
for the slow typers ;) instead.