diff --git a/doc/src/sgml/installation.sgml b/doc/src/sgml/installation.sgml
index 5621606f59a..ebdb5b3bc2d 100644
--- a/doc/src/sgml/installation.sgml
+++ b/doc/src/sgml/installation.sgml
@@ -3582,33 +3582,9 @@ xcrun --show-sdk-path
 
    <para>
     PostgreSQL for Windows can be built using MinGW, a Unix-like build
-    environment for Microsoft operating systems.
-    The MinGW build procedure uses the normal build system described in
-    this chapter.
-   </para>
-
-   <para>
-    MinGW, the Unix-like build tools, and MSYS, a collection
-    of Unix tools required to run shell scripts
-    like <command>configure</command>, can be downloaded
-    from <ulink url="http://www.mingw.org/"></ulink>.  Neither is
-    required to run the resulting binaries; they are needed only for
-    creating the binaries.
-   </para>
-
-   <para>
-     To build 64 bit binaries using MinGW, install the 64 bit tool set
-     from <ulink url="https://mingw-w64.org/"></ulink>, put its bin
-     directory in the <envar>PATH</envar>, and run
-     <command>configure</command> with the
-     <command>--host=x86_64-w64-mingw32</command> option.
-   </para>
-
-   <para>
-    After you have everything installed, it is suggested that you
-    run <application>psql</application>
-    under <command>CMD.EXE</command>, as the MSYS console has
-    buffering issues.
+    environment for Windows.  It is recommended to use the <ulink
+    url="https://www.msys2.org/">MSYS2</ulink> environment for this and also
+    to install any prerequisite packages.
    </para>
 
    <sect3 id="mingw-crash-dumps">
@@ -3838,35 +3814,9 @@ make: *** [postgres] Error 1
         <productname>Bison</productname> and <productname>Flex</productname> are
         required.  Only <productname>Bison</productname> versions 2.3 and later
         will work. <productname>Flex</productname> must be version 2.5.35 or later.
+        Binaries can be downloaded from <ulink
+        url="https://github.com/lexxmark/winflexbison"></ulink>.
        </para>
-
-       <para>
-        Both <productname>Bison</productname> and <productname>Flex</productname>
-        are included in the <productname>msys</productname> tool suite, available
-        from <ulink url="http://www.mingw.org/wiki/MSYS"></ulink> as part of the
-        <productname>MinGW</productname> compiler suite.
-       </para>
-
-       <para>
-        You will need to add the directory containing
-        <filename>flex.exe</filename> and <filename>bison.exe</filename> to the
-        PATH environment variable. In the case of MinGW, the directory is the
-        <filename>\msys\1.0\bin</filename> subdirectory of your MinGW
-        installation directory.
-       </para>
-
-       <note>
-        <para>
-          The Bison distribution from GnuWin32 appears to have a bug that
-          causes Bison to malfunction when installed in a directory with
-          spaces in the name, such as the default location on English
-          installations <filename>C:\Program Files\GnuWin32</filename>.
-          Consider installing into <filename>C:\GnuWin32</filename> or use the
-          NTFS short name path to GnuWin32 in your PATH environment setting
-          (e.g., <filename>C:\PROGRA~1\GnuWin32</filename>).
-         </para>
-       </note>
-
        </listitem>
       </varlistentry>
      </variablelist>
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 06cc42c1f04..9412cad3ac5 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -1017,13 +1017,6 @@ cache_locale_time(void)
  * get ISO Locale name directly by using GetLocaleInfoEx() with LCType as
  * LOCALE_SNAME.
  *
- * MinGW headers declare _create_locale(), but msvcrt.dll lacks that symbol in
- * releases before Windows 8. IsoLocaleName() always fails in a MinGW-built
- * postgres.exe, so only Unix-style values of the lc_messages GUC can elicit
- * localized messages. In particular, every lc_messages setting that initdb
- * can select automatically will yield only C-locale messages. XXX This could
- * be fixed by running the fully-qualified locale name through a lookup table.
- *
  * This function returns a pointer to a static buffer bearing the converted
  * name or NULL if conversion fails.
  *
@@ -1031,8 +1024,6 @@ cache_locale_time(void)
  * [2] https://docs.microsoft.com/en-us/windows/win32/intl/locale-names
  */
 
-#if defined(_MSC_VER)
-
 /*
  * Callback function for EnumSystemLocalesEx() in get_iso_localename().
  *
@@ -1201,16 +1192,6 @@ IsoLocaleName(const char *winlocname)
 		return get_iso_localename(winlocname);
 }
 
-#else							/* !defined(_MSC_VER) */
-
-static char *
-IsoLocaleName(const char *winlocname)
-{
-	return NULL;				/* Not supported on MinGW */
-}
-
-#endif							/* defined(_MSC_VER) */
-
 #endif							/* WIN32 && LC_MESSAGES */