Fixing borderless windows for KDE Plasma

[fire-eggs]

Borderless windows currently doesn't work on KDE plasma. The following chunks of code, pulled from feh is how it implements borderless windows, and it works on KDE.

typedef struct _mwmhints {
	unsigned long flags;
	unsigned long functions;
	unsigned long decorations;
	long input_mode;
	unsigned long status;
} MWMHints;

...
	memset(&mwmhints, 0, sizeof(mwmhints));
	if (opt.borderless || ret->full_screen) {
		prop = XInternAtom(disp, "_MOTIF_WM_HINTS", True);
		if (prop == None) {
			weprintf
			    ("Window Manager does not support MWM hints. "
			     "To get a borderless window I have to bypass your wm.");
			attr.override_redirect = True;
			mwmhints.flags = 0;
		} else {
			mwmhints.flags = MWM_HINTS_DECORATIONS;
			mwmhints.decorations = 0;
		}
	}

...

    // ret->win is the result from XCreateWindow - a Window
	if (mwmhints.flags) {
		XChangeProperty(disp, ret->win, prop, prop, 32,
				PropModeReplace, (unsigned char *) &mwmhints, PROP_MWM_HINTS_ELEMENTS);
	}