squangle transition hack

[Joe Buck <jbuck at synopsys dot com>]

Here's an oddball idea I just came up with to ease the transition to
-fsquangle.  It's analogous to thunks.

Let's say that egcs 1.2 makes -fsquangle the default, and you want to
link your program to an older libstdc++.  If you have what I'll call
"squangle stubs" you can do it.  "squangle stubs" would be a library
of little thunks-style functions that just do jumps to corresponding
functions in the real library (you may not even need thunks, if you
can just install definitions for the new symbols as being equal to
the old symbols).

You can also do the stubs in the reverse direction: build libstdc++
with -fsquangle and add stubs so that -fno-squangle code works.
As this reduces the size of the debug information it's probably better.

The extra symbol might confuse gdb though.