expression which evaluates to zero treated as a null pointer constant of type 'char *'

[ryandesign]

Compiling opendetex 2.8.8 with clang on macOS 10.13.6, I see this warning which might indicate a problem that should be fixed:

detex.l:404:36: warning: expression which evaluates to zero treated as a null pointer constant of type 'char *' [-Wnon-literal-null-conversion]
                                                        rgsbIncList[csbIncList++] = '\0';
                                                                                    ^~~~
1 warning generated.