Update and extend NOTES.WIN, adding 'Quick start' subsection

Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/12098)

NOTES.PERL

@@ -35,9 +35,11 @@
  MinGW and Cygwin. The key recommendation is to use "matching" Perl,
  one that matches build environment. For example, if you will build
  on Cygwin be sure to use the Cygwin package manager to install Perl.
- For MSYS builds use the MSYS provided Perl. For VC-* builds we
- recommend ActiveState Perl, available from
- http://www.activestate.com/ActivePerl.
+ For MSYS builds use the MSYS provided Perl.
+ For VC-* builds we recommend Strawberry Perl, from http://strawberryperl.com.
+ An alternative is ActiveState Perl, from http://www.activestate.com/ActivePerl
+ for which you may need to explicitly select the Perl module Win32/Console.pm
+ available via https://platform.activestate.com/ActiveState.
 
  Notes on Perl on VMS
  --------------------

NOTES.WIN

 
- NOTES FOR THE WINDOWS PLATFORMS
- ===============================
-
- Windows targets can be classified as "native", ones that use Windows API
- directly, and "hosted" which rely on POSIX-compatible layer. "Native"
- targets are VC-* (where "VC" stems from abbreviating Microsoft Visual C
- compiler) and mingw[64]. "Hosted" platforms are Cygwin and MSYS[2]. Even
- though the latter is not directly supported by OpenSSL Team, it's #1
- popular choice for building MinGW targets. In the nutshell MinGW builds
- are always cross-compiled. On Linux and Cygwin they look exactly as such
- and require --cross-compile-prefix option. While on MSYS[2] it's solved
- rather by placing gcc that produces "MinGW binary" code 1st on $PATH.
- This is customarily source of confusion. "Hosted" applications "live" in
- emulated file system name space with POSIX-y root, mount points, /dev
- and even /proc. Confusion is intensified by the fact that MSYS2 shell
- (or rather emulated execve(2) call) examines the binary it's about to
- start, and if it's found *not* to be linked with MSYS2 POSIX-y thing,
- command line arguments that look like file names get translated from
- emulated name space to "native". For example '/c/some/where' becomes
- 'c:\some\where', '/dev/null' - 'nul'. This creates an illusion that
- there is no difference between MSYS2 shell and "MinGW binary", but
- there is. Just keep in mind that "MinGW binary" "experiences" Windows
- system in exactly same way as one produced by VC, and in its essence
- is indistinguishable from the latter. (Which by the way is why
- it's referred to in quotes here, as "MinGW binary", it's just as
- "native" as it can get.)
-
- Visual C++ builds, a.k.a. VC-*
- ==============================
+ NOTES FOR WINDOWS PLATFORMS
+ ===========================
+
+ There are various options to build and run OpenSSL on the Windows platforms.
+
+ "Native" OpenSSL uses the Windows APIs directly at run time.
+ To build a native OpenSSL you can either use:
+
+     Microsoft Visual C++ (MSVC) C compiler on the command line
+ or
+     MinGW cross compiler
+     run on the GNU-like development environment MSYS2
+     or run on Linux or Cygwin
+
+ "Hosted" OpenSSL relies on an external POSIX compatibility layer
+ for building (using GNU/Unix shell, compiler, and tools) and at run time.
+ For this option you can use Cygwin.
+
+
+ Visual C++ native builds, a.k.a. VC-*
+ =====================================
 
  Requirement details
  -------------------
 
- In addition to the requirements and instructions listed in INSTALL,
+ In addition to the requirements and instructions listed in INSTALL.md,
  these are required as well:
 
- - Perl. We recommend ActiveState Perl, available from
-   https://www.activestate.com/ActivePerl. Another viable alternative
-   appears to be Strawberry Perl, http://strawberryperl.com.
-   You also need the perl module Text::Template, available on CPAN.
-   Please read NOTES.PERL for more information.
+ - Perl.
+   We recommend Strawberry Perl, available from http://strawberryperl.com/
+   Please read NOTES.PERL for more information, including the use of CPAN.
+   An alternative is ActiveState Perl, https://www.activestate.com/ActivePerl
+   for which you may need to explicitly build the Perl module Win32/Console.pm
+   via https://platform.activestate.com/ActiveState and then download it.
+
+ - Microsoft Visual C compiler.
+   Since these are proprietary and ever-changing we cannot test them all.
+   Older versions may not work. Use a recent version wherever possible.
+
+ - Netwide Assembler (NASM), available from https://www.nasm.us
+   Note that NASM is the only supported assembler.
+
+ Quick start
+ -----------
+
+ 1. Install Perl
+
+ 2. Install NASM
+
+ 3. Make sure both Perl and NASM are on your %PATH%
+
+ 4. Use Visual Studio Developer Command Prompt with administrative privileges,
+    choosing one of its variants depending on the intended architecture.
+    Or run "cmd" and execute "vcvarsall.bat" with one of the options x86,
+    x86_amd64, x86_arm, x86_arm64, amd64, amd64_x86, amd64_arm, or amd64_arm64.
+    This sets up the environment variables needed for nmake.exe, cl.exe, etc.
+    See also https://docs.microsoft.com/cpp/build/building-on-the-command-line
+
+ 5. From the root of the OpenSSL source directory enter
+    perl Configure VC-WIN32    if you want 32-bit OpenSSL or
+    perl Configure VC-WIN64A   if you want 64-bit OpenSSL
+
+ 6. nmake
 
- - Microsoft Visual C compiler. Since we can't test them all, there is
-   unavoidable uncertainty about which versions are supported. Latest
-   version along with couple of previous are certainly supported. On
-   the other hand oldest one is known not to work. Everything between
-   falls into best-effort category.
+ 7. nmake test
 
- - Netwide Assembler, a.k.a. NASM, available from https://www.nasm.us,
-   is required. Note that NASM is the only supported assembler. Even
-   though Microsoft provided assembler is NOT supported, contemporary
-   64-bit version is exercised through continuous integration of
-   VC-WIN64A-masm target.
+ 8. nmake install
 
+ For the full installation instructions, or if anything goes wrong at any stage,
+ check the INSTALL.md file.
 
  Installation directories
  ------------------------
@@ -83,7 +99,6 @@
  is, of course, to choose a different set of directories by using
  --prefix and --openssldir when configuring.
 
-
  Special notes for Universal Windows Platform builds, a.k.a. VC-*-UWP
  --------------------------------------------------------------------
 
@@ -91,33 +106,56 @@
 
  - You should define the platform type to "uwp" and the target arch via
    "vcvarsall.bat" before you compile. For example, if you want to build
-   "arm64" builds, you should type "vcvarsall.bat x86_arm64 uwp".
+   "arm64" builds, you should run "vcvarsall.bat x86_arm64 uwp".
 
- mingw and mingw64
- =================
 
- * MSYS2 shell and development environment installation:
+ Native OpenSSL built using MinGW
+ ================================
 
-   Download MSYS2 from https://msys2.github.io/ and follow installation
-   instructions. Once up and running install even make, perl, (git if
-   needed,) mingw-w64-i686-gcc and/or mingw-w64-x86_64-gcc. You should
-   have corresponding MinGW items on your start menu, use *them*, not
-   generic MSYS2. As implied in opening note, difference between them
-   is which compiler is found 1st on $PATH. At this point ./config
-   should recognize correct target, roll as if it was Unix...
+ MinGW offers an alternative way to build native OpenSSL, by cross compilation.
 
- * It is also possible to build mingw[64] on Linux or Cygwin by
-   configuring with corresponding --cross-compile-prefix= option. For
-   example
+ * Usually the build is done on Windows in a GNU-like environment called MSYS2.
 
-     ./Configure mingw --cross-compile-prefix=i686-w64-mingw32- ...
+   MSYS2 provides GNU tools, a Unix-like command prompt,
+   and a UNIX compatibility layer for applications.
+   However in this context it is only used for building OpenSSL.
+   The resulting OpenSSL does not rely on MSYS2 to run and is fully native.
+
+   Requirement details
+
+   - MSYS2 shell, from https://www.msys2.org/
+
+   - Perl, at least version 5.10.0, which usually comes pre-installed with MSYS2
+
+   - make, installed using "pacman -S make" into the MSYS2 environment
+
+   - MinGW[64] compiler: mingw-w64-i686-gcc and/or mingw-w64-x86_64-gcc.
+     These compilers must be on your MSYS2 $PATH.
+     A common error is to not have these on your $PATH.
+     The MSYS2 version of gcc will not work correctly here.
+
+   In the MSYS2 shell do the configuration depending on the target architecture:
 
+     ./Configure mingw ...
    or
+     ./Configure mingw64 ...
+   or
+     ./config ...
+   for the default architecture.
+
+   Apart from that, follow the Unix / Linux instructions in INSTALL.md.
+
+ * It is also possible to build mingw[64] on Linux or Cygwin.
+
+   In this case configure with the corresponding --cross-compile-prefix= option.
+   For example
 
+     ./Configure mingw --cross-compile-prefix=i686-w64-mingw32- ...
+   or
      ./Configure mingw64 --cross-compile-prefix=x86_64-w64-mingw32- ...
 
-   This naturally implies that you've installed corresponding add-on
-   packages.
+   This requires that you've installed the necessary add-on packages for
+   mingw[64] cross compilation.
 
  Linking your application
  ========================
@@ -146,28 +184,29 @@
 	}
 
  If you link with OpenSSL .DLLs, then you're expected to include into
- your application code small "shim" snippet, which provides glue between
- OpenSSL BIO layer and your compiler run-time. See the OPENSSL_Applink
- manual page for further details.
+ your application code a small "shim" snippet, which provides
+ the glue between the OpenSSL BIO layer and your compiler run-time.
+ See also the OPENSSL_Applink manual page.
+
 
- Cygwin, "hosted" environment
- ============================
+ Hosted OpenSSL built using Cygwin
+ =================================
 
- Cygwin implements a Posix/Unix runtime system (cygwin1.dll) on top of the
- Windows subsystem and provides a bash shell and GNU tools environment.
- Consequently, a make of OpenSSL with Cygwin is virtually identical to the
+ Cygwin implements a POSIX/Unix runtime system (cygwin1.dll) on top of the
+ Windows subsystem and provides a Bash shell and GNU tools environment.
+ Consequently, a build of OpenSSL with Cygwin is virtually identical to the
  Unix procedure.
 
  To build OpenSSL using Cygwin, you need to:
 
- * Install Cygwin (see https://cygwin.com/)
+ * Install Cygwin, see https://cygwin.com/
 
- * Install Cygwin Perl and ensure it is in the path. Recall that
-   as least 5.10.0 is required.
+ * Install Cygwin Perl, at least version 5.10.0
+   and ensure it is in the $PATH
 
- * Run the Cygwin bash shell
+ * Run the Cygwin Bash shell
 
- Apart from that, follow the Unix instructions in INSTALL.
+ Apart from that, follow the Unix / Linux instructions in INSTALL.md.
 
  NOTE: "make test" and normal file operations may fail in directories
  mounted as text (i.e. mount -t c:\somewhere /home) due to Cygwin