More updates to README.win32 about various compilers

* Visual Studio 2013 is the only version that still has Express edition (in
  addition to Community), so simplify the text by only mentioning Community
* Remove the reference to IA64, and mention x86_64 along with x86
* In the context of x86_64, clarify that mingw's binaries can run on both
* Update the URL for mingw

README.win32

@@ -37,7 +37,7 @@ port of Perl to the Windows platform.  This includes both 32-bit and
 64-bit Windows operating systems.  The resulting Perl requires no
 additional software to run (other than what came with your operating
 system).  Currently, this port is capable of using one of the
-following compilers on the Intel x86 architecture:
+following compilers on the Intel x86 and x86_64 architectures:
 
       Microsoft Visual C++    version 12.0 or later
       Intel C++ Compiler      (experimental)
@@ -49,9 +49,9 @@ delivering complete gcc toolchain for MS Windows:
 
 =over 4
 
-=item L<http://mingw.org>
+=item L<https://osdn.net/projects/mingw/>
 
-Delivers gcc toolchain targeting 32-bit Windows platform.
+Delivers gcc toolchain building 32-bit executables (which can be used both 32 and 64 bit Windows platforms)
 
 =item L<http://mingw-w64.org>
 
@@ -62,26 +62,17 @@ that are also supported by perl's makefile.
 
 =back
 
-The Microsoft Visual C++ compilers are also now being given away free. They are
-available as "Visual C++ 2013-2019 Express [or
-Community, from 2017] Edition" (and also as part of the ".NET Framework SDK")
-and are the same compilers that ship with
-or "Visual C++ 2013-2019 Professional".
+The Microsoft Visual C++ compilers are also now being given away free. They
+are available as "Visual C++ 2013-2019 Community Edition" (and also as part of
+the ".NET Framework SDK") and are the same compilers that ship with "Visual
+C++ 2013-2019 Professional".
 
 Visual C++ 2013 is capable of B<targeting> XP and Windows Server 2003 but the
 build host requirement is Windows 7/Windows Server 2012. For more details see
 https://docs.microsoft.com/en-us/visualstudio/productinfo/vs2013-compatibility-vs
 and
 https://docs.microsoft.com/en-us/visualstudio/productinfo/vs2013-sysrequirements-vs
 
-
-Older versions of perl could also be built on IA64/AMD64 using:
-
-      Microsoft Platform SDK	Nov 2001 (64-bit compiler and tools)
-      MinGW64 compiler (gcc version 4.4.3 or later)
-
-but these have not been tested recently.
-
 The Windows SDK can be downloaded from L<https://developer.microsoft.com/windows/downloads/sdk-archive>.
 The MinGW64 compiler is available at L<http://mingw-w64.org>.
 The latter is actually a cross-compiler targeting Win64. There's also a trimmed
@@ -138,7 +129,7 @@ console already set up for your target architecture (x86-32 or x86-64 or IA64).
 With the newer compilers, you may also use the older batch files if you choose
 so.
 
-=item Microsoft Visual C++ 2013-2019 Express/Community Edition
+=item Microsoft Visual C++ 2013-2019 Community Edition
 
 These free versions of Visual C++ 2013-2019 Professional contain the same
 compilers and linkers that ship with the full versions, and also contain
@@ -150,7 +141,7 @@ L<https://www.microsoft.com/downloads/search.aspx?displaylang=en>.  (Providing e
 links to these packages has proven a pointless task because the links keep on
 changing so often.)
 
-Install Visual C++ 2013-2019 Express/Community, then setup your environment
+Install Visual C++ 2013-2019 Community, then setup your environment
 using, e.g.
 
  C:\Program Files\Microsoft Visual Studio 12.0\Common7\Tools\vsvars32.bat
@@ -171,7 +162,7 @@ shells available after you install the Platform SDK from the Start Menu.
 Perl can be compiled with gcc from MinGW (version 3.4.5 or later) or from
 MinGW64 (version 4.4.3 or later).  It can be downloaded here:
 
-L<http://www.mingw.org/>
+L<https://osdn.net/projects/mingw/>
 L<http://www.mingw-w64.org/>
 
 You also need gmake. Usually it comes with MinGW but its executable may have
@@ -289,7 +280,7 @@ may crash (after all its tests have passed). This is due to a regression in the
 Universal CRT introduced in the Windows 10 April 2018 Update, and will be fixed
 in the May 2019 Update, as explained here: L<https://developercommunity.visualstudio.com/content/problem/519486/setlocalelc-numeric-iso-latin-16-fails-then-succee.html>.
 
-If you build with certain versions (e.g. 4.8.1) of gcc from www.mingw.org then
+If you build with certain versions (e.g. 4.8.1) of gcc from mingw then
 F<ext/POSIX/t/time.t> may fail test 17 due to a known bug in those gcc builds:
 see L<https://sourceforge.net/p/mingw/bugs/2152/>.