Can't build xapian-bindings in a virtual env

Hi,

I'm on a Ubuntu 18.04 server, trying to use django-haystack with xapian
in a python3.6 virtualenv.

The virtualenv is set up not to use system packages, meaning that I
can't just install python3-xapian-haystack with apt, and instead have to
manually build xapian-core and xapian-bindings within the virtualenv.

This works with xapian-core and the --prefix argument to configure. When
I try the same with xapian-bindings, using:

./configure --prefix=$venv --with-python3

The configure process looks fine: xapian-config is found correctly, as
is my virtualenv python installation. Then I export LD_LIBRARY_PATH as
$venv/lib. Then "make" fails with:

make  all-recursive
make[1]: Entering directory '/home/<me>/.local/share/virtualenvs/<venv>/src/xapian-bindings-1.4.7'
Making all in .
make[2]: Entering directory '/home/<me>/.local/share/virtualenvs/<venv>/src/xapian-bindings-1.4.7'
make[2]: Leaving directory '/home/<me>/.local/share/virtualenvs/<venv>/src/xapian-bindings-1.4.7'
Making all in python3
make[2]: Entering directory '/home/<me>/.local/share/virtualenvs/<venv>/src/xapian-bindings-1.4.7/python3'
make  all-am
make[3]: Entering directory '/home/<me>/.local/share/virtualenvs/<venv>/src/xapian-bindings-1.4.7/python3'
depbase=`echo xapian_wrap.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/bash ../libtool  --tag=CXX   --mode=compile g++ -DHAVE_CONFIG_H -I. -I..  -I/usr/include/python3.6m  -fno-strict-aliasing -Wall -Wno-unused -Wno-uninitialized -fvisibility=hidden -I/home/<me>/.local/share/virtualenvs/<venv>/include -g -O2 -MT xapian_wrap.lo -MD -MP -MF $depbase.Tpo -c -o xapian_wrap.lo xapian_wrap.cc &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile:  g++ -DHAVE_CONFIG_H -I. -I.. -I/usr/include/python3.6m -fno-strict-aliasing -Wall -Wno-unused -Wno-uninitialized -fvisibility=hidden -I/home/<me>/.local/share/virtualenvs/<venv>/include -g -O2 -MT xapian_wrap.lo -MD -MP -MF .deps/xapian_wrap.Tpo -c xapian_wrap.cc  -fPIC -DPIC -o .libs/xapian_wrap.o
g++: internal compiler error: Killed (program cc1plus)
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-7/README.Bugs> for instructions.
Makefile:787: recipe for target 'xapian_wrap.lo' failed
make[3]: *** [xapian_wrap.lo] Error 1
make[3]: Leaving directory '/home/<me>/.local/share/virtualenvs/<venv>/src/xapian-bindings-1.4.7/python3'
Makefile:687: recipe for target 'all' failed
make[2]: *** [all] Error 2
make[2]: Leaving directory '/home/<me>/.local/share/virtualenvs/<venv>/src/xapian-bindings-1.4.7/python3'
Makefile:521: recipe for target 'all-recursive' failed
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory '/home/<me>/.local/share/virtualenvs/<venv>/src/xapian-bindings-1.4.7'
Makefile:443: recipe for target 'all' failed
make: *** [all] Error 2

Can anyone tell me how to get this package configured and built
correctly?

Thanks!
Eric