8371967: Add Visual Studio 2026 to build toolchain for Windows

Backport-of: dcba014

Author: MBaesken

doc/building.html

@@ -668,7 +668,7 @@ <h3 id="microsoft-visual-studio">Microsoft Visual Studio</h3>
 (Note that this version is often presented as "MSVC 14.28", and reported
 by cl.exe as 19.28.) Older versions will not be accepted by
 <code>configure</code> and will not work. The maximum accepted version
-of Visual Studio is 2022.</p>
+of Visual Studio is 2026.</p>
 <p>If you have multiple versions of Visual Studio installed,
 <code>configure</code> will by default pick the latest. You can request
 a specific version to be used by setting

doc/building.md

@@ -468,7 +468,7 @@ available for this update.
 The minimum accepted version is Visual Studio 2019 version 16.8. (Note that
 this version is often presented as "MSVC 14.28", and reported by cl.exe as
 19.28.) Older versions will not be accepted by `configure` and will not work.
-The maximum accepted version of Visual Studio is 2022.
+The maximum accepted version of Visual Studio is 2026.
 
 If you have multiple versions of Visual Studio installed, `configure` will by
 default pick the latest. You can request a specific version to be used by

make/autoconf/toolchain_microsoft.m4

@@ -25,7 +25,7 @@
 
 ################################################################################
 # The order of these defines the priority by which we try to find them.
-VALID_VS_VERSIONS="2022 2019"
+VALID_VS_VERSIONS="2022 2019 2026"
 
 VS_DESCRIPTION_2019="Microsoft Visual Studio 2019"
 VS_VERSION_INTERNAL_2019=142
@@ -57,6 +57,21 @@ VS_SDK_PLATFORM_NAME_2022=
 VS_SUPPORTED_2022=true
 VS_TOOLSET_SUPPORTED_2022=true
 
+VS_DESCRIPTION_2026="Microsoft Visual Studio 2026"
+VS_VERSION_INTERNAL_2026=145
+VS_MSVCR_2026=vcruntime140.dll
+VS_VCRUNTIME_1_2026=vcruntime140_1.dll
+VS_MSVCP_2026=msvcp140.dll
+VS_ENVVAR_2026="VS180COMNTOOLS"
+VS_USE_UCRT_2026="true"
+VS_VS_INSTALLDIR_2026="Microsoft Visual Studio/18"
+VS_EDITIONS_2026="BuildTools Community Professional Enterprise"
+VS_SDK_INSTALLDIR_2026=
+VS_VS_PLATFORM_NAME_2026="v145"
+VS_SDK_PLATFORM_NAME_2026=
+VS_SUPPORTED_2026=true
+VS_TOOLSET_SUPPORTED_2026=true
+
 ################################################################################
 
 AC_DEFUN([TOOLCHAIN_CHECK_POSSIBLE_VISUAL_STUDIO_ROOT],