config.sub: Accept LLVM-style $cpu-$vendor-windows-{gnu,msvc}

In older times, MinGW (GCC toolchain with modified windows headers) was
the only free software toolchain for Windows.  But now, LLVM has support
both for MinGW ABI and Microsoft's own.  The distinction matters for C++
more than C.

LLVM[1], Rust[2], and other projects have taken to differentiating these
two as `...windows-gnu` vs `...windows-msvc`.  I think that makes a lot
of sense, as it correctly identifiers both their commonalities and their
differences.

A lot of MinGW-supporting software, most notably GCC itself, will
presumably continue to use configs like x86_64-pc-mingw32 and
i686-pc-mingw32.  That's fine; this patch doesn't normalize them away
(like LLVM does) or remove them!  If and when that software wants to
support the MSVC ABI without requiring MSVC itself, they can switch to
these newer configurations.

[1]: a18266473b/llvm/unittests/TargetParser/TripleTest.cpp (L1907-L1951)
[2]: 36fb58e433/compiler/rustc_target/src/spec/mod.rs (L1255-L1271)

config.sub

@@ -4,7 +4,7 @@
 
 # shellcheck disable=SC2006,SC2268 # see below for rationale
 
-timestamp='2023-06-23'
+timestamp='2023-06-26'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -145,7 +145,8 @@ case $1 in
 			nto-qnx* | linux-* | uclinux-uclibc* \
 			| uclinux-gnu* | kfreebsd*-gnu* | knetbsd*-gnu* | netbsd*-gnu* \
 			| netbsd*-eabi* | kopensolaris*-gnu* | cloudabi*-eabi* \
-			| storm-chaos* | os2-emx* | rtmk-nova* | managarm-*)
+			| storm-chaos* | os2-emx* | rtmk-nova* | managarm-* \
+			| windows-* )
 				basic_machine=$field1
 				basic_os=$maybe_os
 				;;
@@ -1766,7 +1767,7 @@ case $os in
 		;;
 	none)
 		;;
-	kernel* )
+	kernel* | msvc* )
 		# Restricted further below
 		;;
 	*)
@@ -1785,6 +1786,8 @@ case $kernel-$os in
 		;;
 	managarm-mlibc* | managarm-kernel* )
 		;;
+	windows*-gnu* | windows*-msvc*)
+		;;
 	-dietlibc* | -newlib* | -musl* | -relibc* | -uclibc* | -mlibc* )
 		# These are just libc implementations, not actual OSes, and thus
 		# require a kernel.
@@ -1799,6 +1802,10 @@ case $kernel-$os in
 		echo "Invalid configuration '$1': '$kernel' does not support '$os'." 1>&2
 		exit 1
 		;;
+	*-msvc* )
+		echo "Invalid configuration '$1': '$os' needs 'windows'." 1>&2
+		exit 1
+		;;
 	kfreebsd*-gnu* | kopensolaris*-gnu*)
 		;;
 	vxworks-simlinux | vxworks-simwindows | vxworks-spe)

doc/config.sub.1

@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.48.5.
-.TH CONFIG.SUB "1" "June 2023" "GNU config.sub (2023-06-23)" "User Commands"
+.TH CONFIG.SUB "1" "July 2023" "GNU config.sub (2023-06-26)" "User Commands"
 .SH NAME
 config.sub \- validate and canonicalize a configuration triplet
 .SH SYNOPSIS

testsuite/config-sub.data

@@ -865,6 +865,8 @@ x86_64-sortix					x86_64-pc-sortix
 x86_64-twizzler				x86_64-pc-twizzler
 x86_64-unknown-ptx				x86_64-sequent-ptx
 x86_64-windows					x86_64-pc-windows
+x86_64-windows-gnu				x86_64-pc-windows-gnu
+x86_64-windows-msvc				x86_64-pc-windows-msvc
 x86_64-wrs-vxworks				x86_64-wrs-vxworks
 x86_64-wrs-vxworks-simlinux			x86_64-wrs-vxworks-simlinux
 x86_64-wrs-vxworks-simwindows			x86_64-wrs-vxworks-simwindows