Define feature test macro needed for realpath(3).

Fix buffer sizes.

Use more conventional syntax for usage help.

Reformat help message and mention --save-cwd.

Add -s alias to --save-cwd and check its argument.

Make --save-cwd work with relative path as argument.

Use const when possible.

Make prompt strings configurable.

Fix failed try_to_sel() after creating directory.

Fix behavior for empty inputs.

Let scroll correction to update_view() when possible.

Remove wrap-around behavior from 'j' & 'k'. That behavior provided a way to easily move between the top and bottom of listing. However, this is no longer needed due to the recent addition of 'g' & 'G'. The new behavior is also more similar to what we are used to in other programs.

Only change scroll if necessary.

Reorganize string buffers. Global buffers used to have descriptive names, but as the need to more temporary buffer appears we have to decide between creating new global buffers or reusing existing ones disregarding their names. Therefore, to avoid the creation of too many buffers or the use of confusing variable names, this change give more generic names to buffers, except for INPUT, which is only used for input. The wide buffer has been made into a global buffer. All global string buffers now have the same size, BUFLEN.

Remove some unnecessary parentheses.