Import upstream Diehard4 by obscurant

Verbatim contents of the upstream GitHub archive (Diehard4-master.zip,
commit 254ee204deebc64793123a9643c85b7d113c6c22, files dated 2019-05-21).

Imported unmodified so that every change in this fork is visible as a diff
against the original, which is what GPL-3.0 section 5(a) is asking for.
All code in this commit is obscurant's work, not mine.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

xfwm4/maximize-active.xpm

@@ -0,0 +1,29 @@
+/* XPM */
+static char * maximize_active_xpm[] = {
+"13 13 13 1",
+" 	c #0D151D",
+".	c #0E171F",
+"+	c #101A24",
+"@	c #111B25",
+"#	c #0D151C",
+"$	c #0C141B",
+"%	c #101922",
+"&	c #0C131B",
+"*	c #5E6E7D",
+"=	c #5A6A79",
+"-	c #556574",
+";	c #516170",
+">	c #0D161E",
+"             ",
+" .+@@@@@@@+. ",
+" +@@@@@@@@@+#",
+" @@@@@@@@@@@$",
+" @@@@+%+@@@@&",
+" @@@+%*%+@@@&",
+" @@+%===%+@@&",
+" @@%--%--%@@&",
+" @@%;%+%;%@@&",
+" @@+%+@+%+@@&",
+" +@@@@@@@@@+&",
+" .+@@@@@@@+>$",
+"  #$&&&&&&&$#"};