Restore proplist.c, which was clobbered by mistake during a rebase.

Lessons learned: don't rebase so freely, review commits properly.

WINGs/proplist.c

@@ -0,0 +1,30 @@
+#include <stdarg.h>
+
+#include "WUtil.h"
+
+/*
+ * This should be written in Rust whenever va_args support improves.
+ */
+WMPropList *WMCreatePLArray(WMPropList * elem, ...)
+{
+	WMPropList *plist, *nelem;
+	va_list ap;
+
+	plist = WMCreateEmptyPLArray();
+
+	if (!elem)
+		return plist;
+
+	WMAddToPLArray(plist, elem);
+
+	va_start(ap, elem);
+
+	while (1) {
+		nelem = va_arg(ap, WMPropList *);
+		if (!nelem) {
+			va_end(ap);
+			return plist;
+		}
+		WMAddToPLArray(plist, elem);
+	}
+}