Hi,

I am running guile-2.0 and guile-2.2 alongside each other which is
causing me some pain*).

This is what bits of my GUILE_LOAD_COMPILED_PATH look like

    /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/lib/guile/2.2/ccache
    --> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/lib/guile/2.2/ccache/ice-9/and-let-star.go

    /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site/2.2/
    --> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site/2.2/os/process.go

If `/<effective-version>' is always used as the suffix of each path
element, and we/guix/packagers do not include that suffix in GUILE_*PATH
elements, then Guile can append effective-prefix and different major
Guile-versions can happily share the same GUILE_LOAD[_COMPILED]_PATH,
e.g., having

    GUILE_LOAD_COMPILED_PATH=/gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site

then guile-2.0 would get (os process) from

    /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site + /2.0
    --> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site/2.0/os/process.go

and guile-2.2 would read

    /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site + /2.2
    --> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site/2.2/os/process.go
    
What do you think?  No more pain!  Find patch attached.

Greetings,
Jan


*) Some of my pain

My Debian host system has guile-2.0, guix depends on guile-2.0, guix's
LD script depends on guile-2.0, the guile bits of my project depend on
guile-2.2.

I have some scripts to make this situation almost bearable, but still I
regularly

cannot find a basic library

    [1]13:53:25 janneke@janneke-ijzer:~
    $ guile --no-auto-compile
    GNU Guile 2.0.11
    Copyright (C) 1995-2014 Free Software Foundation, Inc.

    Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
    This program is free software, and you are welcome to redistribute it
    under certain conditions; type `,show c' for details.

    Enter `,help' for help.
    scheme@(guile-user)> (use-modules (os proccess))
    While compiling expression:
    ERROR: no code for module (os proccess)

or some guile script (guix) aborts

    guix environment --ad-hoc ccache coreutils git guix emacs guile-next guile-next-lib
    Throw without catch before boot:
    Throw to key misc-error with args ("make_objcode_from_file" "bad header on object file: ~s" ("\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00") #f)Aborting.
    Aborted

or linking breaks

    g++ -Wall -std=c++11  -g -I. -I out/alarm.project/c++ -I check/alarm.project/   out/alarm.project/c++/main.o out/alarm.project/c++/Alarm.o out/alarm.project/c++/AlarmSystem.o out/alarm.project/c++/pump.o out/alarm.project/c++/runtime.o    -lboost_system -lboost_coroutine -lboost_thread -lboost_context -pthread -o out/alarm.project/c++/test
    collect2: error: ld terminated with signal 6 [Afgebroken]
    Throw without catch before boot:
    Aborting.

and then I juggle installed guile versions and/or manually modify
GUILE_LOAD_COMPILED_PATH.