Building with --enable-debug fails with error: ‘_assert’ was not declared in this scope

If I configure like this:

configure --with-module=fabricate \
             LDFLAGS="-rdynamic" \
             --enable-runtime-loading \
             --enable-debug \
             --with-boost \
             --prefix=/usr/local \
             --enable-install_test_progs=no \
             --with-umfpack \
             --with-metis=no \
             --with-ginac=yes \
             CXXFLAGS="$CXXFLAGS -std=c++11" \
             CPPFLAGS="$CPPFLAGS -I/usr/include/suitesparse"

I get the following error:

libtool: compile:  g++ -DHAVE_CONFIG_H -I. -I../../include -I../../include -I./../../include -I./../../libraries/libmbutil -I./../../libraries/libmbmath -I./../../mbdyn -I/usr/include/suitesparse -std=c++11 -pthread -MT mynewmem.lo -MD -MP -MF .deps/mynewmem.Tpo -c mynewmem.cc  -fPIC -DPIC -o .libs/mynewmem.o
myassert.cc: In function ‘void _Assert(const char*, int, const char*)’:
myassert.cc:82:4: error: ‘_assert’ was not declared in this scope
    _assert(msg, file, line);
    ^~~~~~~
myassert.cc:82:4: note: suggested alternative: ‘_Assert’
    _assert(msg, file, line);
    ^~~~~~~
    _Assert

This is on Ubuntu 18.04