pyosys: globals, set operators for opaque types

There is so much templating going on that compiling wrappers.cc now takes 1m1.668s on an Apple M4…

tests/pyosys/test_set.py

@@ -0,0 +1,42 @@
+# -*- coding: utf-8 -*-
+from pyosys.libyosys import StringSet, StringPool
+
+for cls in [StringSet, StringPool]:
+	print(f"Testing {cls.__name__}...")
+	A = cls()
+	A.add("a")
+
+	B = cls()
+	B = A | {"b"}
+
+	assert A < B
+	assert A <= B
+
+	A.add("b")
+
+	assert A == B
+	assert A <= B
+	assert not A < B
+
+	A.add("c")
+
+	assert A > B
+
+	A &= B
+	assert A == B
+
+	Ø = A - B
+	assert len(Ø) == 0
+
+	C = cls({"A", "B", "C"})
+	D = cls()
+	C |= {"A", "B", "C"}
+	D |= {"C", "D", "E"}
+	c_symdiff_d = (C ^ D)
+	assert (c_symdiff_d) == {"A", "B", "D", "E"}
+
+	repr_test = eval(repr(c_symdiff_d))
+	c_symdiff_d == repr_test
+
+
+print("Done.")