OpenSSL::config: determine the MSVC target architecture by asking cl

Since cl knows what architecture it builds fore, all depending on what
the user set up, it makes sense to ask it, and use that result primarly,
and only use the POSIX::uname() MACHINE value as a fallback.

Also, this does indeed determine if cl is present or not.

We drop the explicit names in .github/workflows/windows.yml as proof
of concept.

Fixes #19281

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19285)

.github/workflows/windows.yml

@@ -22,9 +22,9 @@ jobs:
           - windows-2022
         platform:
           - arch: win64
-            config: VC-WIN64A enable-fips
+            config: enable-fips
           - arch: win32
-            config: VC-WIN32 --strict-warnings no-fips
+            config: --strict-warnings no-fips
     runs-on: ${{matrix.os}}
     steps:
     - uses: actions/checkout@v2
@@ -95,7 +95,7 @@ jobs:
     - name: config
       working-directory: _build
       run: |
-        perl ..\Configure --banner=Configured no-makedepend no-bulk no-deprecated no-fips no-asm -DOPENSSL_SMALL_FOOTPRINT VC-WIN64A
+        perl ..\Configure --banner=Configured no-makedepend no-bulk no-deprecated no-fips no-asm -DOPENSSL_SMALL_FOOTPRINT
         perl configdata.pm --dump
     - name: build
       working-directory: _build

util/perl/OpenSSL/config.pm

@@ -32,6 +32,7 @@ my $SYSTEM;
 my $VERSION;
 my $CCVENDOR;
 my $CCVER;
+my $CL_ARCH;
 my $GCC_BITS;
 my $GCC_ARCH;
 
@@ -378,6 +379,22 @@ sub determine_compiler_settings {
                 $CCVER = $v;
             }
         }
+
+        # 'Windows NT' is the system name according to POSIX::uname()!
+        if ( $SYSTEM eq "Windows NT" ) {
+            # favor vendor cl over gcc
+            if (IPC::Cmd::can_run('cl')) {
+                $CC = 'cl';
+                $CCVENDOR = ''; # Determine later
+                $CCVER = 0;
+
+                my $v = `cl 2>&1`;
+                if ( $v =~ /Microsoft .* Version ([0-9\.]+) for (x86|x64|ARM|ia64)/ ) {
+                    $CCVER = $1;
+                    $CL_ARCH = $2;
+                }
+            }
+        }
     }
 
     # If no C compiler has been determined at this point, we die.  Hard.
@@ -884,9 +901,33 @@ EOF
       ],
 
       # Windows values found by looking at Perl 5's win32/win32.c
-      [ 'amd64-.*?-Windows NT',   { target => 'VC-WIN64A' } ],
-      [ 'ia64-.*?-Windows NT',    { target => 'VC-WIN64I' } ],
-      [ 'x86-.*?-Windows NT',     { target => 'VC-WIN32'  } ],
+      [ '(amd64|ia64|x86|ARM)-.*?-Windows NT',
+        sub {
+            # If we determined the arch by asking cl, take that value,
+            # otherwise the SYSTEM we got from from POSIX::uname().
+            my $arch = $CL_ARCH // $1;
+            my $config;
+
+            if ($arch) {
+                $config = { 'amd64' => { target => 'VC-WIN64A'    },
+                            'ia64'  => { target => 'VC-WIN64I'    },
+                            'x86'   => { target => 'VC-WIN32'     },
+                            'x64'   => { target => 'VC-WIN64A'    },
+                            'ARM'   => { target => 'VC-WIN64-ARM' },
+                          } -> {$arch};
+                die <<_____ unless defined $config;
+ERROR
+I do not know how to handle ${arch}.
+_____
+            }
+            die <<_____ unless defined $config;
+ERROR
+Could not figure out the architecture.
+_____
+
+            return $config;
+        }
+      ],
 
       # VMS values found by observation on existing machinery.
       # Unfortunately, the machine part is a bit...  overdone.  It seems,