bug#27157: Building Guile 2.2 "times out"

[Maxim Cournoyer]

The build errors out with:

--8<---------------cut here---------------start------------->8---
  SNARF  weak-set.doc
  SNARF  weak-table.doc
  SNARF  weak-vector.doc
  SNARF  posix.doc
  SNARF  net_db.doc
  SNARF  socket.doc
  SNARF  regex-posix.doc
  CCLD     libguile-2.2.la
.libs/libguile_2.2_la-posix.o: In function `scm_tmpnam':
/tmp/guix-build-guile-2.2.2.drv-0/guile-2.2.2/libguile/posix.c:1574: warning: 
the use of `tmpnam' is dangerous, better use `mkstemp'
  CCLD     guile
  GEN      guile-procedures.texi
make[3]: Leaving directory 
'/tmp/guix-build-guile-2.2.2.drv-0/guile-2.2.2/libguile'
make[2]: Leaving directory 
'/tmp/guix-build-guile-2.2.2.drv-0/guile-2.2.2/libguile'
Making all in bootstrap
make[2]: Entering directory 
'/tmp/guix-build-guile-2.2.2.drv-0/guile-2.2.2/bootstrap'
  BOOTSTRAP GUILEC ice-9/eval.go
wrote `ice-9/eval.go'
  BOOTSTRAP GUILEC ice-9/psyntax-pp.go
  BOOTSTRAP GUILEC language/cps/intmap.go
building of `/gnu/store/i2p0gqxm378ydlh58qpy6jas7rdk79jg-guile-2.2.2.drv' timed 
out after 3600 seconds of silence
cannot build derivation
  `/gnu/store/c34w733549bjvcdixb0yj306ydhwv8c3-guile2.2-gnutls-3.5.9.drv':
  1 dependencies couldn't be built
--8<---------------cut here---------------end--------------->8---

I'm not sure where this timeout value can be configured, but clearly it
shouldn't be 1 hour since 2 cores of an i5 intel class processor can't
manage to build it under 1 hour.

Maxim