Add support for Visual Studio 2026 in pre-17 build scripts

Documentation and any code paths related to VS are updated to keep the
whole consistent. Similar to what was done for VS 2017, 2019 and 2022.

Reviewed-by: Michael Paquier <michael@paquier.xyz>
Backpatch: 14 through 16
Discussion: https://postgr.es/m/CAD5tBc+nFmaqqCaxDdQUMtOmtTb3nrvXn2TiVjLQyy0FV1BcUQ@mail.gmail.com

doc/src/sgml/install-windows.sgml

@@ -20,9 +20,9 @@
  <para>
   There are several different ways of building PostgreSQL on
   <productname>Windows</productname>. The simplest way to build with
-  Microsoft tools is to install <productname>Visual Studio 2022</productname>
+  Microsoft tools is to install <productname>Visual Studio 2026</productname>
   and use the included compiler. It is also possible to build with the full
-  <productname>Microsoft Visual C++ 2013 to 2022</productname>.
+  <productname>Microsoft Visual C++ 2013 to 2026</productname>.
   In some cases that requires the installation of the
   <productname>Windows SDK</productname> in addition to the compiler.
  </para>
@@ -69,7 +69,7 @@
   <productname>Microsoft Windows SDK</productname>. If you do not already have a
   <productname>Visual Studio</productname> environment set up, the easiest
   ways are to use the compilers from
-  <productname>Visual Studio 2022</productname> or those in the
+  <productname>Visual Studio 2026</productname> or those in the
   <productname>Windows SDK 10</productname>, which are both free downloads
   from Microsoft.
  </para>
@@ -78,7 +78,7 @@
   Both 32-bit and 64-bit builds are possible with the Microsoft Compiler suite.
   32-bit PostgreSQL builds are possible with
   <productname>Visual Studio 2013</productname> to
-  <productname>Visual Studio 2022</productname>,
+  <productname>Visual Studio 2026</productname>,
   as well as standalone Windows SDK releases 8.1a to 10.
   64-bit PostgreSQL builds are supported with
   <productname>Microsoft Windows SDK</productname> version 8.1a to 10 or
@@ -86,7 +86,7 @@
   is supported down to <productname>Windows 7</productname> and
   <productname>Windows Server 2008 R2 SP1</productname> when building with
   <productname>Visual Studio 2013</productname> to
-  <productname>Visual Studio 2022</productname>.
+  <productname>Visual Studio 2026</productname>.
    <!--
        For 2013 requirements:
        https://docs.microsoft.com/en-us/visualstudio/productinfo/vs2013-sysrequirements-vs
@@ -98,6 +98,8 @@
        https://docs.microsoft.com/en-us/visualstudio/releases/2019/system-requirements
        For 2022 requirements:
        https://docs.microsoft.com/en-us/visualstudio/releases/2022/system-requirements
+       For 2026 requirements:
+       https://docs.microsoft.com/en-us/visualstudio/releases/2026/vs-system-requirements
    -->
  </para>
 

src/tools/msvc/MSBuildProject.pm

@@ -533,4 +533,29 @@ sub new
 	return $self;
 }
 
+package VC2026Project;
+
+#
+# Package that encapsulates a Visual C++ 2026 project file
+#
+
+use strict;
+use warnings;
+use base qw(MSBuildProject);
+
+no warnings qw(redefine);    ## no critic
+
+sub new
+{
+	my $classname = shift;
+	my $self      = $classname->SUPER::_new(@_);
+	bless($self, $classname);
+
+	$self->{vcver}           = '18.00';
+	$self->{PlatformToolset} = 'v145';
+	$self->{ToolsVersion}    = '18.0';
+
+	return $self;
+}
+
 1;

src/tools/msvc/README

@@ -4,7 +4,7 @@ MSVC build
 ==========
 
 This directory contains the tools required to build PostgreSQL using
-Microsoft Visual Studio 2013 - 2022. This builds the whole backend, not just
+Microsoft Visual Studio 2013 - 2026. This builds the whole backend, not just
 the libpq frontend library. For more information, see the documentation
 chapter "Installation on Windows" and the description below.
 
@@ -89,11 +89,12 @@ These configuration arguments are passed over to Mkvcbuild::mkvcbuild
 (Mkvcbuild.pm) which creates the Visual Studio project and solution files.
 It does this by using VSObjectFactory::CreateSolution to create an object
 implementing the Solution interface (this could be either VS2013Solution,
-VS2015Solution, VS2017Solution, VS2019Solution or VS2022Solution, all in
-Solution.pm, depending on the user's build environment) and adding objects
-implementing the corresponding Project interface (VC2013Project,
-VC2015Project, VC2017Project, VC2019Project or VC2022Project from
-MSBuildProject.pm) to it. When Solution::Save is called, the implementations
+VS2015Solution, VS2017Solution, VS2019Solution, VS2022Solution or
+VS2026Solution, all in Solution.pm, depending on the user's build
+environment) and adding objects implementing the corresponding Project
+interface (VC2013Project, VC2015Project, VC2017Project, VC2019Project,
+VC2022Project or VC2026Project from MSBuildProject.pm) to it. When
+Solution::Save is called, the implementations
 of Solution and Project save their content in the appropriate format.
 The final step of starting the appropriate build program (msbuild) is
 performed in build.pl again.

src/tools/msvc/Solution.pm

@@ -1357,6 +1357,34 @@ sub new
 	return $self;
 }
 
+package VS2026Solution;
+
+#
+# Package that encapsulates a Visual Studio 2026 solution file
+#
+
+use Carp;
+use strict;
+use warnings;
+use base qw(Solution);
+
+no warnings qw(redefine);    ## no critic
+
+sub new
+{
+	my $classname = shift;
+	my $self      = $classname->SUPER::_new(@_);
+	bless($self, $classname);
+
+	$self->{solutionFileVersion}        = '12.00';
+	$self->{vcver}                      = '18.00';
+	$self->{visualStudioName}           = 'Visual Studio 2026';
+	$self->{VisualStudioVersion}        = '18.7.11925.98';
+	$self->{MinimumVisualStudioVersion} = '10.0.40219.1';
+
+	return $self;
+}
+
 sub GetAdditionalHeaders
 {
 	my ($self, $f) = @_;

src/tools/msvc/VSObjectFactory.pm

@@ -63,14 +63,24 @@ sub CreateSolution
 	}
 
 	# The version of nmake bundled in Visual Studio 2022 is greater
-	# than 14.30 and less than 14.40.  And the version number is
+	# than 14.30 and less than 14.50.  And the version number is
 	# actually 17.00.
 	elsif (
-		($visualStudioVersion ge '14.30' && $visualStudioVersion lt '14.40')
+		($visualStudioVersion ge '14.30' && $visualStudioVersion lt '14.50')
 		|| $visualStudioVersion eq '17.00')
 	{
 		return new VS2022Solution(@_);
 	}
+
+	# The version of nmake bundled in Visual Studio 2026 is greater
+	# than 14.50 and less than 14.60.  And the version number is
+	# actually 18.00.
+	elsif (
+		($visualStudioVersion ge '14.50' && $visualStudioVersion lt '14.60')
+		|| $visualStudioVersion eq '18.00')
+	{
+		return new VS2026Solution(@_);
+	}
 	else
 	{
 		croak
@@ -117,14 +127,24 @@ sub CreateProject
 	}
 
 	# The version of nmake bundled in Visual Studio 2022 is greater
-	# than 14.30 and less than 14.40.  And the version number is
+	# than 14.30 and less than 14.50.  And the version number is
 	# actually 17.00.
 	elsif (
-		($visualStudioVersion ge '14.30' && $visualStudioVersion lt '14.40')
+		($visualStudioVersion ge '14.30' && $visualStudioVersion lt '14.50')
 		|| $visualStudioVersion eq '17.00')
 	{
 		return new VC2022Project(@_);
 	}
+
+	# The version of nmake bundled in Visual Studio 2026 is greater
+	# than 14.50 and less than 14.60.  And the version number is
+	# actually 18.00.
+	elsif (
+		($visualStudioVersion ge '14.50' && $visualStudioVersion lt '14.60')
+		|| $visualStudioVersion eq '18.00')
+	{
+		return new VC2026Project(@_);
+	}
 	else
 	{
 		croak
@@ -154,7 +174,7 @@ sub DetermineVisualStudioVersion
 	else
 	{
 		# fake version
-		return '17.00';
+		return '18.00';
 	}
 }
 
@@ -163,13 +183,13 @@ sub _GetVisualStudioVersion
 	my ($major, $minor) = @_;
 
 	# The major visual studio that is supported has nmake
-	# version <= 14.40, so stick with it as the latest version
+	# version <= 14.60, so stick with it as the latest version
 	# if bumping on something even newer.
-	if ($major >= 14 && $minor >= 40)
+	if ($major >= 14 && $minor >= 60)
 	{
 		carp
 		  "The determined version of Visual Studio is newer than the latest supported version. Returning the latest supported version instead.";
-		return '14.30';
+		return '14.50';
 	}
 	elsif ($major < 12)
 	{