Fill .ws_xpixel and .ws_ypixel values in winsize

[Kruna1Pate1]

This allows to get terminal size in pixels using TIOCGWINSZ ioctl.

Set .ws_xpixel using columns * cell_width and set .ws_ypixel using rows * cell_height. Cell width and height are font width and line spacing, respectively.

Before

~ $ ./size
rows: 29, cols: 48, xpixel: 0, ypixel: 0
~ $ ./size
rows: 26, cols: 44, xpixel: 0, ypixel: 0
~ $ ./size
rows: 23, cols: 39, xpixel: 0, ypixel: 0
~ $

After

~ $ ./size
rows: 29, cols: 48, xpixel: 1056, ypixel: 1160
~ $ ./size
rows: 26, cols: 44, xpixel: 1056, ypixel: 1144
~ $ ./size
rows: 23, cols: 39, xpixel: 1053, ypixel: 1150
~ $

Use this snippet to check behaviour,

#include <sys/ioctl.h>
#include <stdio.h>
#include <unistd.h>

int main(void) {
    struct winsize ws;
    ioctl(STDIN_FILENO, TIOCGWINSZ, &ws);

    printf("rows: %d, cols: %d, xpixel: %d, ypixel: %d \n", ws.ws_row, ws.ws_col, ws.ws_xpixel, ws.ws_ypixel);

    return 0;
}

Closes: #3092

[agnostic-apollo]

Thanks, will look into it.