third_party/libcxxabi: Add test suite (#1076)

Added the `libcxxabi` test suite as found in LLVM 17.0.6.

Some tests that do not apply to the current configuration of
comsopolitan are not added. These include:
- `backtrace_test`, `forced_unwind*`: Use unwind function unsupported in
SjLj mode.
- `noexception*`: Designed to test `libcxxabi` in no exceptions mode.

Some tests are added but not enabled due to bugs specific to GCC or
cosmopolitan. These are clearly indicated in the `BUILD.mk` file.

third_party/libcxxabi/test/catch_ptr_02.pass.cc

@@ -0,0 +1,217 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: no-exceptions
+
+// Compilers emit warnings about exceptions of type 'Child' being caught by
+// an earlier handler of type 'Base'. Congrats, you've just diagnosed the
+// behavior under test.
+// ADDITIONAL_COMPILE_FLAGS: -Wno-exceptions
+
+// The fix for PR17222 made it in the dylib for macOS 10.10
+// XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx10.9
+
+#include "third_party/libcxx/cassert"
+#include "libc/isystem/stdint.h"
+
+#if __cplusplus < 201103L
+#define DISABLE_NULLPTR_TESTS
+#endif
+
+struct  A {};
+A a;
+const A ca = A();
+
+void test1 ()
+{
+    try
+    {
+        throw &a;
+        assert(false);
+    }
+    catch ( const A* )
+    {
+    }
+    catch ( A *)
+    {
+        assert (false);
+    }
+}
+
+void test2 ()
+{
+    try
+     {
+        throw &a;
+        assert(false);
+    }
+    catch ( A* )
+    {
+    }
+    catch ( const A *)
+    {
+         assert (false);
+    }
+}
+
+void test3 ()
+{
+    try
+    {
+        throw &ca;
+        assert(false);
+    }
+    catch ( const A* )
+    {
+    }
+    catch ( A *)
+    {
+        assert (false);
+    }
+}
+
+void test4 ()
+{
+    try
+    {
+        throw &ca;
+        assert(false);
+    }
+    catch ( A *)
+    {
+        assert (false);
+    }
+    catch ( const A* )
+    {
+    }
+}
+
+struct base1 {int x;};
+struct base2 {int x;};
+struct derived : base1, base2 {};
+
+void test5 ()
+{
+    try
+    {
+        throw (derived*)0;
+        assert(false);
+    }
+    catch (base2 *p) {
+        assert (p == 0);
+    }
+    catch (...)
+    {
+        assert (false);
+    }
+}
+
+void test6 ()
+{
+#if !defined(DISABLE_NULLPTR_TESTS)
+    try
+    {
+        throw nullptr;
+        assert(false);
+    }
+    catch (base2 *p) {
+        assert (p == nullptr);
+    }
+    catch (...)
+    {
+        assert (false);
+    }
+#endif
+}
+
+void test7 ()
+{
+    try
+    {
+        throw (derived*)12;
+        assert(false);
+    }
+    catch (base2 *p) {
+        assert ((uintptr_t)p == 12+sizeof(base1));
+    }
+    catch (...)
+    {
+        assert (false);
+    }
+}
+
+
+struct vBase {};
+struct vDerived : virtual public vBase {};
+
+void test8 ()
+{
+    vDerived derived;
+    try
+    {
+        throw &derived;
+        assert(false);
+    }
+    catch (vBase *p) {
+        assert(p != 0);
+    }
+    catch (...)
+    {
+        assert (false);
+    }
+}
+
+void test9 ()
+{
+#if !defined(DISABLE_NULLPTR_TESTS)
+    try
+    {
+        throw nullptr;
+        assert(false);
+    }
+    catch (vBase *p) {
+        assert(p == 0);
+    }
+    catch (...)
+    {
+        assert (false);
+    }
+#endif
+}
+
+void test10 ()
+{
+    try
+    {
+        throw (vDerived*)0;
+        assert(false);
+    }
+    catch (vBase *p) {
+        assert(p == 0);
+    }
+    catch (...)
+    {
+        assert (false);
+    }
+}
+
+int main(int, char**)
+{
+    test1();
+    test2();
+    test3();
+    test4();
+    test5();
+    test6();
+    test7();
+    test8();
+    test9();
+    test10();
+
+    return 0;
+}