Better handling of package errors when LOAD or LOADFROM or READFILE

[masinter]

Currently, there are situations where processing a file will generate an error if there is a symbol with package prefix which doesn't match the current package configuration, for example FOO:BAZ when BAZ is not exported from the FOO package. Perhaps if you are LOADing the file for executing you want the error? But for some workflows where the downstream application is limited, an error isn't really appropriate.

For computing 'whereis.hash' for example, package errors result in the file not being indexed if it has package errors. And HCFILES just wants to pretty-print the file contents.

So the idea i'd like to explore is making reading in a file for some purposes to substitute something else for the "broken symbol" which PRETTYFILEINDEX or MAKE-WHEREIS-HASH (or whatever it's called) will printout or index the "broken symbol" appropriately.

It might be possible to delay the error condition to the runtime when the symbol is first encountered, rather than at LOAD or READ time.

I chose "broken symbol" because SEDIT has something like this, and fixing SEDIT to handle broken symbols seems necessary.