To build in a separate directory, you must use a version of `make'
that supports the `VPATH' variable, such as GNU `make'.
-3c) Some people try to build in a separate directory
-by filling it full of symlinks to the real source directory.
+3c) Some people try to build in a separate directory by filling
+it full of symlinks to the files in the real source directory.
If you do that, `make all' does work, but `make install' fails:
it copies the symbolic links rather than the actual files.