Time to fork a guile-2 branch?

[Ian Hulin]

Dear all, (especially David and Graham)
Contrary to all indications, I have actually been slowly (very slowly)
chugging away on this, developing on my netbook.

In order to achieve this, we'll need produce a series of patches.  The
criterion for accepting the patch for guile V1 systems would, as ever,
be - do no harm, run the regtests without change.

1. Add conditionally compiled/executed code in main.cc where necessary
for using differing calls for guile V1 and guile V2, the guile 1
branches remaining the same. This is now mostly complete, subject to
changes required by steps 2 and 3.

2. Add new lily-guile2.scm, this is lily.scm re-written to use new
(include-from-path) guile macro instead of loading component files.
The current code in lily.scm is copied unchanged to lily-guile1.scm
and the lily.scm becomes a shim with
(cond-expand (guile-2
                (include-from-path "lily-guile2.scm"))
             (guile
                (load-from-path "lily-guile1.scm")))

3. Where there are significant changes to component .scm files for
guile V2, these will also be converted into a shim similar to lily.scm
and will have <file>-guile-1.scm and <file>-guile-2.scm files produced.

Given that these patches will be quite extensive, is now a good time
to set up a guile-2 branch in git, forking off from the start of the
V2.17.0 development?

If the answer is yes, I may need some hand-holding/support to make
sure I don't do any damage to the main git repository.

Sorry I won't be able to make the developer's meeting at Waltrop, but
I'll be on a flute summer course in France between 22 and 30 August.

Cheers,

Ian Hulin