If the compile time option SQLITE_ENABLE_MULTIPLEX is defined, then the following code section of the SQLite shell source code will be compiled:

#ifdef SQLITE_ENABLE_MULTIPLEX
    }else if( cli_strcmp(z,"-multiplex")==0 ){
      extern int sqlite3_multiple_initialize(const char*,int);
      sqlite3_multiplex_initialize(0, 1);
#endif

However, the function name in the extern statement is mispelled, and that could lead to runtime errors. It should read sqlite3_multiplex_initialize, that is multiplex instead of multiple.