ConfigLocations_create():
  Creates a config file location handle
ConfigLocations_fgets():
  Read a line from the current config file that is open
ConfigLocations_open_file():
  Open a new current config file
ConfigLocations_open_folder():
  Open all config files (sorted alphanumerically) from a folder
ConfigLocations_open_glob():
  Open all config files matching a fnmatch/glob pattern
ConfigLocations_close()
  Close the current config file (and move to next)
ConfigLocations_free()
  Close all config files and free all resources

The fgets method also returns the line number/file path of the current file

As we process the lines returned by fgets we're able to ask the
handle to open a new pattern:

```C
    int debug_flag = 1
    const char * config_file_path = "my_config.conf";
    char buffer[1024];
    const char * current_file;
    int current_line_number;

    struct ConfigLocations *handle = ConfigLocations_create();
    ConfigLocations_open_file(handle, config_file_path, debug_flag);

    while (ConfigLocations_fgets(handle, &buffer, sizeof(buffer),
                                &current_file, &current_line_number,
                                debug_flag))
    {
        // Remove new line
        chat * end = strchr(buffer, '\n');
        if (end) *end = '\0';

        // Dump current file, line number, and line that was read:
        printf("%s[%d]: Read \"%s\"\n", current_file, line_number, buffer);

        // Look for lines starting "include "
        // We'll use this as an instruction to include additional files
        if (memcmp(buffer, "include ", sizeof("include ")-1) == 0) {
            // Remove the "include " from the start of the line
            char * pattern = buffer + sizeof("include ") - 1;
            // Treat the remainder as a glob:
            ConfigLocations_open_glob(handle, pattern, debug_flag);
            // Continue with the read loop that will now jump
            // to the included files
            continue;
        }
        // Do something with the config file lines we read
    }
    ConfigLocations_free(handle);
```

In this demo, we parse our config file (my_config.conf).
When we encounter a line "include glob_patter", we resolve all the
files that match this pattern and open them in order.

Each call to ConfigLocations_fgets reads from the current file
At EOF, it jumps to the next file matching the current glob
before finally returned back to the previous file

After a line like:
  include my_config.d/*.conf

each subsequent call to fgets will return a line from each *.conf file in that folder
before resuming reading from my_config.conf

…ective

Using the ConfigLocations methods, the options fgets loop now supports
including additional config files based on the glob set in the config

the fgets call will stop reading the current file and start reading from
each config file that matched the pattern/glob before finally resuming
the original config file.

The number of inclusions is limited by the CONFIG_RECURSION_DEPTH defined
in the configlocations.h

Used in the options.c loop that reads from the config file