Doc build hanging (with memory leak?)

[Joseph Rushton Wakeling]

Hello all,

I've successfully build Lilypond itself from source, but when I try to make doc, 
the build hangs on the first file it attempts to compile:

make[3]: Entering directory `/home/joseph/code/lily/build/input/regression'
LILYPOND_VERSION=2.15.39 /usr/bin/python 
/home/joseph/code/lily/scripts/lilypond-book.py -I 
/home/joseph/code/lily/input/regression/ -I ./out-www -I 
/home/joseph/code/lily/input -I /home/joseph/code/lily/Documentation -I 
/home/joseph/code/lily/Documentation/snippets -I 
/home/joseph/code/lily/input/regression/ -I 
/home/joseph/code/lily/Documentation/included/ -I 
/home/joseph/code/lily/build/mf/out/ -I /home/joseph/code/lily/build/mf/out/ -I 
/home/joseph/code/lily/Documentation/pictures -I 
/home/joseph/code/lily/build/Documentation/pictures/./out-www 
--process='/home/joseph/code/lily/build/out/bin/lilypond -I 
/home/joseph/code/lily/input/regression/ -I ./out-www -I 
/home/joseph/code/lily/input -I /home/joseph/code/lily/Documentation -I 
/home/joseph/code/lily/Documentation/snippets -I 
/home/joseph/code/lily/input/regression/ -I 
/home/joseph/code/lily/Documentation/included/ -I 
/home/joseph/code/lily/build/mf/out/ -I /home/joseph/code/lily/build/mf/out/ -I 
/home/joseph/code/lily/Documentation/pictures -I 
/home/joseph/code/lily/build/Documentation/pictures/./out-www -dbackend=eps 
--formats=ps,png,pdf  -dinclude-eps-fonts -dgs-load-fonts --header=doctitle 
--header=doctitlecs --header=doctitlede --header=doctitlees --header=doctitlefr 
--header=doctitlehu --header=doctitleit --header=doctitleja --header=doctitlenl 
--header=doctitlezh --header=texidoc --header=texidoccs --header=texidocde 
--header=texidoces --header=texidocfr --header=texidochu --header=texidocit 
--header=texidocja --header=texidocnl --header=texidoczh -dcheck-internal-types 
-ddump-signatures -danti-alias-factor=2' --output=./out-www --format=texi-html 
--loglevel=WARN  --lily-output-dir /home/joseph/code/lily/build/out/lybook-db 
--redirect-lilypond-output out-www/collated-files.tely
langdefs.py: warning: lilypond-doc gettext domain not found.

Checking 'top' shows that the memory consumption of Lilypond is steadily 
increasing over time, but nothing appears to actually be happening.

This is completely at odds with the last doc builds I attempted for Lilypond, 
probably late last year.  Is this a bug, or is the doc build system just 
operating differently?

Thanks and best wishes,

    -- Joe