Problems with make check and guile, apparently

[Colin Law]

I am having getting make check to pass for reasons unknown to me.  In
src/engine/test/test-suite.log I see

====================================================
   GnuCash 2.6.12: src/engine/test/test-suite.log
====================================================

# TOTAL: 27
# PASS:  24
# SKIP:  0
# XFAIL: 0
# FAIL:  3
# XPASS: 0
# ERROR: 0

.. contents:: :depth: 2

FAIL: test-test-extras
======================

;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
;;;       or pass the --no-auto-compile argument to disable.
;;; compiling /home/colinl/apps/gnucash_git/src/engine/test/./test-test-extras.scm
;;; WARNING: compilation of
/home/colinl/apps/gnucash_git/src/engine/test/./test-test-extras.scm
failed:
;;; ERROR: no code for module (gnucash engine test test-extras)
Backtrace:
In ice-9/boot-9.scm:
 157: 17 [catch #t #<catch-closure 1d5d560> ...]
In unknown file:
   ?: 16 [apply-smob/1 #<catch-closure 1d5d560>]
In ice-9/boot-9.scm:
  63: 15 [call-with-prompt prompt0 ...]
In ice-9/eval.scm:
 432: 14 [eval # #]
In ice-9/boot-9.scm:
2401: 13 [save-module-excursion #<procedure 1d7ba40 at
ice-9/boot-9.scm:4045:3 ()>]
4052: 12 [#<procedure 1d7ba40 at ice-9/boot-9.scm:4045:3 ()>]
1724: 11 [%start-stack load-stack ...]
1729: 10 [#<procedure 29da600 ()>]
In unknown file:
   ?: 9 [primitive-load
"/home/colinl/apps/gnucash_git/src/engine/test/./test-test-extras.scm"]
In ice-9/eval.scm:
 505: 8 [#<procedure 1c2d3e0 at ice-9/eval.scm:499:4 (exp)> (use-modules #)]
In ice-9/psyntax.scm:
1106: 7 [expand-top-sequence ((use-modules (gnucash engine test ...))) () ...]
 989: 6 [scan ((use-modules (gnucash engine test ...))) () ...]
 279: 5 [scan ((# #) #(syntax-object *unspecified* # #)) () (()) ...]
In ice-9/boot-9.scm:
3597: 4 [process-use-modules (((gnucash engine test test-extras)))]
 702: 3 [map #<procedure 1ceda00 at ice-9/boot-9.scm:3597:25 (mif-args)> ((#))]
3598: 2 [#<procedure 1ceda00 at ice-9/boot-9.scm:3597:25 (mif-args)> (#)]
2867: 1 [resolve-interface (gnucash engine test ...) #:select ...]
In unknown file:
   ?: 0 [scm-error misc-error #f ...]

ERROR: In procedure scm-error:
ERROR: no code for module (gnucash engine test test-extras)
FAIL test-test-extras (exit status: 1)

Followed by several other similar reports.  Having searched the list I
found suggestions to delete ~/.cache/guile/ccache but that did not
help, in fact I tried deleting ~/.cache/guile but again I still get
the error.  A few days ago make check was ok but I don't know what I
may have done to mess it up.  The only file modified (from the maint
branch) is gnc-backend-dbi.c which does not appear to be related to
the problem.

This is running on Ubuntu 16.04.

Any help will be much appreciated.

Colin