Unwrapped paths in config.sub and config.guess

[Edgar Costa]

Hello,

The variables configfsf_{sub,guess} that hold paths in the scripts
config.{sub,guess} should be wrapped in quotes, e.g.,
$SHELL $configfsf_guess
should be called as
$SHELL "$configfsf_guess"

Here is a patch in case you are interested:
https://gist.github.com/edgarcosta/328016a479f4545640d61a3542e5f9c0


This is partially moot, as the need for quotes there might be an indicator
of an "unsafe srcdir value", which is only checked later in the configure;
nonetheless, that error message would be more clear.

Best,
Edgar