installation problem with egcs 970828 on alpha-dec-osf4.0

[Jim Wilson]

We could just always use the install script.  This is what the toplevel
makefile does, and I believe there is no problem if you make install from
the toplevel directory because it passes down its definition of INSTALL.

We could also delete the duplicate install scripts in the tree.  There
are at least two of them, install-sh and gcc/install.sh.

Jim