Re: `read' is now >200x slower than under 9.2 and 10.1.10.

[Taylor R Campbell]

> Date: Fri, 1 May 2020 21:33:06 -0700
> From: "Arthur A. Gleckler" <address@hidden>
> 
> It went perfectly on my Mac and fine on my Linux laptop after I made a link
> from /usr/local/bin/mit-scheme-x86-64 to
> /usr/local/bin/mit-scheme-x86-64-10.90, but consistently fails on my Linux
> instance at Linode, even after I made the link in /usr/local/bin/ and an
> analogous link in /usr/local/lib/.  I made the links after initial failures
> under the theory that the build was using the binary 10.1.10 distribution
> instead of the new 10.90 build.

What I do is keep them always installed in separate prefixes with
./configure --prefix, and use PATH to choose them:

/usr/local/mit-scheme/10.1.9
/usr/local/mit-scheme/10.1.10
/usr/local/mit-scheme/master-20200430

Then, e.g.:

env -i PATH=/bin:/usr/bin:/usr/local/mit-scheme/10.1.10/bin ./Setup.sh

(For my own interactive use I also put a symlink in ~/usr/bin, which
is in my normal PATH, so I can still just type `scheme' to start it
up, but using `env -i PATH=...' ensures nothing accidentally gets
that.)

> The error I get is:
> 
> ;Unable to find file "edwin.bld" because: File does not exist.

I feel like I ran into this a couple months ago but I forget what the
resolution was.

> This happens even from maintainer-clean.  All systems at c87066ff.

I don't trust maintainer-clean, because the makefiles aren't very good
at being around at all the right times; I always use `git clean -dxn'
(and review what it will delete to make sure it's nothing important)
and then `git clean -dxf'.