32-bit Clang Release Builds failing ww8export Unit Tests

With both 32-bit Ubuntu 14.04 and 16.04, and Clang 3.8-40, and the following autogen.input:
--without-export-validation
--disable-firebird-sdbc
CC=clang
CXX=clang++

I'm getting the following build failure:
[CUT] sw_ww8export
...
testN325936::Import_Export_Import finished in: 421ms
File tested,Execution Time (ms)
tscp.doc:
184
testTscp::Import finished in: 197ms
File tested,Execution Time (ms)
tscp.doc:
361
testTscp::Import_Export_Import finished in: 376ms
testFdo45724::Import finished in: 1ms
File tested,Execution Time (ms)
Segmentation fault (core dumped)

No core file identified in directory /core/workdir/CppunitTest/sw_ww8export.test.core
To show backtraces for crashes during test execution,
enable core files with:

   ulimit -c unlimited


Error: a unit test failed, please do one of:
make CppunitTest_sw_ww8export CPPUNITTRACE="gdb --args"
    # for interactive debugging on Linux
make CppunitTest_sw_ww8export VALGRIND=memcheck
    # for memory checking
make CppunitTest_sw_ww8export DEBUGCPPUNIT=TRUE
    # for exception catching

/core/solenv/gbuild/CppunitTest.mk:101: recipe for target 
'/core/workdir/CppunitTest/sw_ww8export.test' failed
make[1]: *** [/core/workdir/CppunitTest/sw_ww8export.test] Error 1
make[1]: *** Waiting for unfinished jobs....
Makefile:263: recipe for target 'build' failed
make: *** [build] Error 2

Debug builds and "--enable-symbols", build without any issues. 

Why would symbols be necessary? Does it also disable optimizations?