bpo-44009: Provide "python3.x-intel64" for Apple Silicon Macs (GH-25804)

This allows reliably forcing macOS universal2 framework builds
to run under Rosetta 2 Intel-64 emulation on Apple Silicon Macs
if needed for testing or when universal2 wheels are not yet
available.
diff --git a/configure b/configure
index 4dc0eab..86591e2 100755
--- a/configure
+++ b/configure
@@ -752,6 +752,7 @@
 PYTHONFRAMEWORKDIR
 PYTHONFRAMEWORKIDENTIFIER
 PYTHONFRAMEWORK
+LIPO_INTEL64_FLAGS
 LIPO_32BIT_FLAGS
 ARCH_RUN_32BIT
 UNIVERSALSDK
@@ -1519,11 +1520,12 @@
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
   --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
   --with-universal-archs=ARCH
-                          specify the kind of universal binary that should be
-                          created. this option is only valid when
+                          specify the kind of macOS universal binary that
+                          should be created. This option is only valid when
                           --enable-universalsdk is set; options are:
-                          ("universal2", "32-bit", "64-bit", "3-way", "intel",
-                          "intel-32", "intel-64", or "all") see Mac/README.rst
+                          ("universal2", "intel-64", "intel-32", "intel",
+                          "32-bit", "64-bit", "3-way", or "all") see
+                          Mac/README.rst
   --with-framework-name=FRAMEWORK
                           specify the name for the python framework on macOS
                           only valid when --enable-framework is set. see
@@ -3139,6 +3141,7 @@
 fi
 
 
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-universal-archs" >&5
 $as_echo_n "checking for --with-universal-archs... " >&6; }
 
@@ -7522,6 +7525,7 @@
 $as_echo "$CC" >&6; }
         fi
 
+        LIPO_INTEL64_FLAGS=""
         if test "${enable_universalsdk}"
         then
             case "$UNIVERSAL_ARCHS" in
@@ -7543,8 +7547,9 @@
             universal2)
                UNIVERSAL_ARCH_FLAGS="-arch arm64 -arch x86_64"
                LIPO_32BIT_FLAGS=""
+               LIPO_INTEL64_FLAGS="-extract x86_64"
                ARCH_RUN_32BIT="true"
-		;;
+               ;;
             intel)
                UNIVERSAL_ARCH_FLAGS="-arch i386 -arch x86_64"
                LIPO_32BIT_FLAGS="-extract i386"