01a8e88116d5f00b16e8441a5d459215bb51e916 documentation: explain preprocessor error

================================ DYNARE MAKE CHECK MATLAB RESULTS ================================ | TOTAL: 199 | PASS: 195 | FAIL: 3 | XFAIL: 1 | XPASS: 0 | LIST OF FAILED TESTS: | * block_bytecode/run_ls2003.m(0,1,8,0) | * block_bytecode/run_ls2003.m(0,1,2,3) | * block_bytecode/run_ls2003.m(1,0,2,3)

================================ DYNARE MAKE CHECK OCTAVE RESULTS ================================ | TOTAL: 197 | PASS: 195 | FAIL: 1 | XFAIL: 1 | XPASS: 0 | LIST OF FAILED TESTS: | * block_bytecode/run_ls2003.m(1,0,2,3)

A full log can be found on karaba in '/tmp/dynare-master-check-NNT31wbWop.log'.