ExtraMaus is a tool that shows an additional mouse cursor. Useful for VLC recording. Author: Dodger Tools

extramaus.c

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <unistd.h>
#include <X11/Xlib.h>
#include <X11/cursorfont.h>
#include <X11/extensions/shape.h>

// Include the mouse cursor xbm directly
#define mouse_width 12
#define mouse_height 21
static unsigned char mouse_bits[] = {
   0x01, 0x00, 0x03, 0x00, 0x07, 0x00, 0x0f, 0x00, 0x1f, 0x00, 0x3f, 0x00,
   0x7f, 0x00, 0xff, 0x00, 0xff, 0x01, 0xff, 0x03, 0xff, 0x07, 0xff, 0x0f,
   0xff, 0x00, 0xff, 0x00, 0xe7, 0x01, 0xe3, 0x01, 0xc1, 0x03, 0xc0, 0x03,
   0x80, 0x07, 0x80, 0x07, 0x00, 0x03 };

/*
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

    Some ideas taken from oneko-1.2.sakura (http://www.daidouji.com/oneko/)
    and shape.c (http://www.edwardrosten.com/code/).

    Compile with: gcc extramaus.c -o extramaus -lX11 -lXext -g
*/


int main(argc, argv) int argc; char *argv[];
{
    Display                 *display;
    int                     screenNr;
    Colormap                colorMap;
    XSetWindowAttributes    windowAttributes;
    Pixmap                  mouseCursor;
    XColor                  red, exact_red;
    Window                  mouseWindow, QueryRoot, QueryChild;
    int                     mouseX, mouseY, winX, winY, mouseOldX, mouseOldY;
    unsigned int            mask;
    XSizeHints              *s_hints;
    XWindowChanges          windowChanges;
    unsigned long           windowMask;

    // Open the X11 display and get back a pointer to it
    display = XOpenDisplay(NULL);

    // Get the screen number
    screenNr = DefaultScreen(display);

    // Get the color map (ID)
    colorMap = DefaultColormap(display, screenNr);

    // Stop the program, if display is false (NULL)
    assert(display);

    // Get the "nearest" color matching the color name "red" and store it in the variable "red"
    XAllocNamedColor(display, colorMap, "red", &red, &exact_red);

    // Set the mouse coordinates to invalid values
    mouseOldX = -1;
    mouseOldY = -1;

    // Set some attributes
    windowAttributes.background_pixel = red.pixel;
    windowAttributes.override_redirect = True;
    windowMask = CWBackPixel | CWOverrideRedirect;

    // Create the window at position 10, 10, with width and height of the cursor
    mouseWindow = XCreateWindow(display, XRootWindow(display, screenNr), 10, 10, mouse_width, mouse_height, 0, DefaultDepth(display, screenNr), InputOutput, CopyFromParent, windowMask, &windowAttributes);
    assert(mouseWindow);

    // Create a bitmap with the size of the mouse cursor and its bits
    mouseCursor = XCreateBitmapFromData(display, mouseWindow, mouse_bits, mouse_width, mouse_height);

    // Use the mouse cursor as shape for the mouse window
    XShapeCombineMask(display, mouseWindow, ShapeBounding, 0, 0, mouseCursor, ShapeSet);

    // Show the mouse window
    XMapWindow(display, mouseWindow);
    XFlush(display);

    // Let it loop forever
    while (True)
    {
        // Get the position of the mouse and store it in the variables mouseX and mouseY
        XQueryPointer(display,DefaultRootWindow(display),&QueryRoot, &QueryChild,&mouseX,&mouseY,&winX,&winY,&mask);

        // Check, if the mouse was moved since the last time
        if ((mouseOldX != mouseX) || (mouseOldY != mouseY))
        {
            // Change the position of the mouse window to x+1 and y+1. +1 because without the normal mouse wouldn't be able to click on things anymore.
            windowChanges.x = mouseX+1;
            windowChanges.y = mouseY+1;
            XConfigureWindow(display, mouseWindow, CWX | CWY, &windowChanges);

            // Store the new mouse coordinates
            mouseOldX = mouseX;
            mouseOldY = mouseY;

            // Update the display
            XFlush(display);
        }

        // Make a pause of 1/100 seconds to save
        usleep(10000);
    }
}

Source: http://dodger-tools.sourceforge.net/cms/index.php?id=100000201
Fix: I added a missing header

Compile with gcc extramaus.c -o extramaus -lX11 -lXext -g as suggested here

I used your gist as a source for archlinux aur package: https://aur.archlinux.org/packages/extramaus

I used your gist as a source for archlinux aur package: https://aur.archlinux.org/packages/extramaus

Glad to see that it was useful!