Spock crashes on MacOS 10.12.6, V8 segfault

I used to be able to run Spock just fine on my machine, either with cluster_run or running regular builds. After a recent update to either the OS or Xcode, it now fails to successfully start up, with the 'beam' processes repeatedly crashing.

According to the Mac console, the crash is happening here:

Thread 15 Crashed:
0 libjemalloc.2.dylib 0x00000001080c8eb2 ifree + 354
1 libjemalloc.2.dylib 0x00000001080c94a3 je_free + 371
2 libv8.dylib 0x000000010a104069 v8::internal::Logger::SetUp(v8::internal::Isolate*) + 1913
3 libv8.dylib 0x000000010a0de7a8 v8::internal::Isolate::Init(v8::internal::Deserializer*) + 4888
4 libv8.dylib 0x000000010a319a74 v8::internal::Snapshot::Initialize(v8::internal::Isolate*) + 756
5 libv8.dylib 0x0000000109bf7007 v8::IsolateNewImpl(v8::internal::Isolate*, v8::Isolate::CreateParams const&) + 471
6 mapreduce_nif.so 0x00000001077469da initContext(map_reduce_ctx_t*, std::_1::list<std::1::basic_string<char, std::1::char_traits<char>, NifStlAllocator<char> >, NifStlAllocator<std::1::basic_string<char, std::_1::char_traits<char>, NifStlAllocator<char> > > > const&, view_index_type_t) + 170 (mapreduce.cc:197)
7 mapreduce_nif.so 0x00000001077439b2 startMapContext(enif_environment_t*, int, unsigned long const*) + 434 (mapreduce_nif.cc:108)
8 beam.smp 0x0000000104583938 process_main + 42088
9 beam.smp 0x00000001044ec8bd sched_thread_func + 477
10 beam.smp 0x00000001045fdf02 thr_wrapper + 146
11 libsystem_pthread.dylib 0x00007fff9e3ca93b _pthread_body + 180
12 libsystem_pthread.dylib 0x00007fff9e3ca887 _pthread_start + 286
13 libsystem_pthread.dylib 0x00007fff9e3ca08d thread_start + 13

Vulcan works just fine on my machine, but it has a newer version of V8.

My Mac is running Sierra, 10.12.6, and Xcode version 9.2 (9C40b).