make: *** No rule to make target `/Makefile', needed by `Makefile'. Stop.

I have two different machines with LLVM source trees on them.
One builds fine, the other gives the error above.

This behavior started on Tuesday.
Both machines have the sources on a non-boot disk.

The source trees are identical, and in both cases, I have a separate object directory.
I have removed the object directories, and reran configure:
  mkdir llvm-build
  cd llvm-build
  ../llvm/configure

Still get the same behavior (success on one, failure on the other).

$ make -v

GNU Make 3.81
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.

This program built for i386-apple-darwin10.0

The only differences that I can think of are:
1) The unsuccessful machine has recently had XCode 4 installed.
2) The successful machine has the sources on a volume with a case-sensitive file system.

Any ideas?

-- Marshall

Marshall Clow Idio Software <mailto:mclow.lists@gmail.com>

A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait).
        -- Yu Suzuki