lang/swift6: Unbreak build with clang 21

Clang 21 appears to have a regression in wchar.h handling when c++20
modules funcationality is enabled. (Swift compiler uses clang's
modules function under the hood.)

This is a workaround to avoid a compilation error by defining the
macro _WCHAR_H_CPLUSPLUS_98_CONFORMANCE_ to 1 before the compiler
reads the system wchar.h.

PR:		296000
Reported by:	Tomoaki AOKI <junchoon@dec.sakura.ne.jp>
Tested by:	Tomoaki AOKI <junchoon@dec.sakura.ne.jp>

lang/swift6: Update to 6.3.3

Release Announcement: https://forums.swift.org/t/announcing-swift-6-3-3/87888

Reported by:	GitHub (watch releases)

lang/swift6: Unbreak stage phase with unprivileged users

Stripping should have been done before COPYTREE_BIN, which drops the
writable bit from the executables and leads to "permission denied"
error.

PR:		296382
Reported by:	kib
Tested by:	kib
Fixes:		18ac8a4bf341 (lang/swift6: Add port: Powerful, flexible, multiplatform
programming language (Version 6))

lang/swift6: Add port: Powerful, flexible, multiplatform programming language
(Version 6)

Swift is the only language that scales from embedded devices and
kernels to apps and cloud infrastructure. It's simple, and
expressive, with incredible performance and safety. And it has
unmatched interoperability with C and C++.

It's the combination of approachability, speed, safety, and all of
Swift's strengths that make it so unique.

WWW: https://www.swift.org/

PR:		296000
Differential Revision:	https://reviews.freebsd.org/D57541

lang/swift6: Repocopy from lang/swift510

PR:		296000