Make Windows 10 the minimal runtime requirement for WIN32

This commit bumps the runtime value of _WIN32_WINNT to be 0x0A00 for any
builds on Windows.  Hence, this makes Windows 10 the minimal requirement
when running PostgreSQL under WIN32, be it for builds of Cygwin, MinGW
or Visual Studio.

The previous minimal runtime version was either Windows Vista when
building with at least Visual Studio 2015 or Windows XP for the rest.

Windows 10 is the most modern version supported by Microsoft, and per
discussion, as we don't have buildfarm members that run older versions
anymore, this is the minimal supported version that suits better for our
needs.  This will actually make easier the development of some patches,
two being async I/O and large page handling by avoiding a lot of
compatibility gotchas, on platforms that have most likely few users
anyway.

It is possible to remove MIN_WINNT in win32.h and the macros
IsWindowsXXXOrGreater() that were used in the code at runtime to check
which version of Windows was getting used.  The change in pg_locale.c
comes from Juan.  Note that all my tests passed, and that the CI is
green.  The buildfarm will quickly tell if this needs more adjustments.

Author: Michael Paquier, Juan José Santamaría Flecha
Reviewed-by: Thomas Munro
Discussion: https://postgr.es/m/Yo7tHKD8VCkeNi71@paquier.xyz

2 files changed, 6 insertions, 12 deletions

diff --git a/doc/src/sgml/install-windows.sgml b/doc/src/sgml/install-windows.sgml
index bcfd5a1a106..66567d17a04 100644
--- a/doc/src/sgml/install-windows.sgml
+++ b/doc/src/sgml/install-windows.sgml
@@ -82,11 +82,7 @@
   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
-  <productname>Visual Studio 2013</productname> and above. Compilation
-  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 2013</productname> and above.
    <!--
        For 2013 requirements:
        https://docs.microsoft.com/en-us/visualstudio/productinfo/vs2013-sysrequirements-vs
@@ -358,8 +354,7 @@ $ENV{MSBFLAGS}="/m";
   <title>Special Considerations for 64-Bit Windows</title>
 
   <para>
-   PostgreSQL will only build for the x64 architecture on 64-bit Windows, there
-   is no support for Itanium processors.
+   PostgreSQL will only build for the x64 architecture on 64-bit Windows.
   </para>
 
   <para>
diff --git a/doc/src/sgml/installation.sgml b/doc/src/sgml/installation.sgml
index c5850780291..c12de7896c5 100644
--- a/doc/src/sgml/installation.sgml
+++ b/doc/src/sgml/installation.sgml
@@ -2136,7 +2136,7 @@ export MANPATH
 
   <para>
    <productname>PostgreSQL</productname> can be expected to work on these operating
-   systems: Linux (all recent distributions), Windows (XP and later),
+   systems: Linux (all recent distributions), Windows (10 and later),
    FreeBSD, OpenBSD, NetBSD, macOS, AIX, HP/UX, and Solaris.
    Other Unix-like systems may also work but are not currently
    being tested.  In most cases, all CPU architectures supported by
@@ -2323,16 +2323,15 @@ ERROR:  could not load library "/opt/dbs/pgsql/lib/plperl.so": Bad address
      <listitem>
       <para>
        The <command>adduser</command> command is not supported; use
-       the appropriate user management application on Windows NT,
-       2000, or XP.  Otherwise, skip this step.
+       the appropriate user management application on Windows.
+       Otherwise, skip this step.
       </para>
      </listitem>
 
      <listitem>
       <para>
        The <command>su</command> command is not supported; use ssh to
-       simulate su on Windows NT, 2000, or XP. Otherwise, skip this
-       step.
+       simulate su on Windows. Otherwise, skip this step.
       </para>
      </listitem>