ao_string_tokenize - tokenize an input string

       This  function  will  convert one input string into a list of strings.  The list of strings is derived by
       separating the input based on white space separation.  However, if the input contains  either  single  or
       double quote characters, then the text after that character up to a matching quote will become the string
       in the list.

       The  returned  pointer  should  be  deallocated with free(3C) when are done using the data.  The data are
       placed in a single block of allocated memory.  Do not deallocate individual token/strings.

       The structure pointed to will contain at least these two fields:

       tkn_ct The number of tokens found in the input string.

       tok_list An array of tkn_ct+1 pointers to substring tokens, with the last pointer set to NULL.

       There are two types of quoted strings: single quoted (') and double quoted (").   Singly  quoted  strings
       are  fairly  raw  in  that  escape characters (\) are simply another character, except when preceding the
       following characters:
           \  double backslashes reduce to one
           '   incorporates the single quote into the string
           0fPsuppressesboththebackslashandnewlinecharacterDoublequotestringsareformedaccordingtotherulesofstringconstantsinANSI-Cprograms.string string to be tokenized

       NULL is returned and errno will be set to indicate the problem:

       EINVAL - There was an unterminated quoted string.

       ENOENT - The input string was empty.

       ENOMEM - There is not enough memory.  @end itemize

                #include <stdlib.h>
                int ix;
                token_list_t * ptl = ao_string_tokenize(some_string)
                for (ix = 0; ix < ptl->tkn_ct; ix++)
                do_something_with_tkn(ptl->tkn_list[ix]);
                free(ptl);
            Note that everything is freed with the one call to free(3C).

       ao_string_tokenize - tokenize an input string

       pointer to a structure that lists each token

       The info documentation for the -lopts library.
       configFileLoad(3),   optionFileLoad(3),   optionFindNextValue(3),   optionFindValue(3),    optionFree(3),
       optionGetValue(3),   optionLoadLine(3),   optionMemberList(3),   optionNextValue(3),  optionOnlyUsage(3),
       optionPrintVersion(3),      optionPrintVersionAndReturn(3),      optionProcess(3),      optionRestore(3),
       optionSaveFile(3),    optionSaveState(3),    optionUnloadNested(3),    optionVersion(3),    strequate(3),
       streqvcmp(3), streqvmap(3), strneqvcmp(3), strtransform(3),

                                                   2018-08-26                              ao_string_tokenize(3)

       #include <your-opts.h>
       cc [...] -o outfile infile.c -lopts [...]

       token_list_t * ao_string_tokenize(char const * string);