From 6e665424d6e7abf6d6de010609a398a7407df83c Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Sat, 21 Nov 2020 17:54:08 -0800
Subject: [PATCH] bpo-38443: Check that the specified universal architectures
 work (GH-22910)

As [bpo-38443]() says the error message from configure when specifying --enable-universalsdk with a set of architectures that is not supported by the compiler is not very helpful.   This PR explicitly checks if the compiler works and bails out if it doesn't.
(cherry picked from commit 0f20bd9042c9b7fce20c3b9511cd0820b30094c3)

Co-authored-by: Ronald Oussoren <ronaldoussoren@mac.com>
---
 .../2020-10-23-10-26-53.bpo-38443.vu64tl.rst  |  2 ++
 configure                                     | 25 +++++++++++++++++++
 configure.ac                                  |  7 ++++++
 3 files changed, 34 insertions(+)
 create mode 100644 Misc/NEWS.d/next/macOS/2020-10-23-10-26-53.bpo-38443.vu64tl.rst

diff --git a/Misc/NEWS.d/next/macOS/2020-10-23-10-26-53.bpo-38443.vu64tl.rst b/Misc/NEWS.d/next/macOS/2020-10-23-10-26-53.bpo-38443.vu64tl.rst
new file mode 100644
index 00000000000..008c972e5c6
--- /dev/null
+++ b/Misc/NEWS.d/next/macOS/2020-10-23-10-26-53.bpo-38443.vu64tl.rst
@@ -0,0 +1,2 @@
+The ``--enable-universalsdk`` and ``--with-universal-archs`` options for the
+configure script now check that the specified architectures can be used.
diff --git a/configure b/configure
index 96dcd0dcd5f..dfb6e7ef3f0 100755
--- a/configure
+++ b/configure
@@ -7493,6 +7493,31 @@ $as_echo_n "checking which MACOSX_DEPLOYMENT_TARGET to use... " >&6; }
         { $as_echo "$as_me:${as_lineno-$LINENO}: result: $MACOSX_DEPLOYMENT_TARGET" >&5
 $as_echo "$MACOSX_DEPLOYMENT_TARGET" >&6; }
 
+        { $as_echo "$as_me:${as_lineno-$LINENO}: checking if specified universal architectures work" >&5
+$as_echo_n "checking if specified universal architectures work... " >&6; }
+        cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdio.h>
+int
+main ()
+{
+printf("%d", 42);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+             as_fn_error $? "check config.log and use the '--with-universal-archs' option" "$LINENO" 5
+
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+
         # end of Darwin* tests
         ;;
     esac
diff --git a/configure.ac b/configure.ac
index 18a044629a7..6c8fd5a3892 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1931,6 +1931,13 @@ yes)
         EXPORT_MACOSX_DEPLOYMENT_TARGET=''
         AC_MSG_RESULT($MACOSX_DEPLOYMENT_TARGET)
 
+        AC_MSG_CHECKING(if specified universal architectures work)
+        AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>]], [[printf("%d", 42);]])],
+            [AC_MSG_RESULT(yes)],
+            [AC_MSG_RESULT(no)
+             AC_MSG_ERROR(check config.log and use the '--with-universal-archs' option)
+        ])
+
         # end of Darwin* tests
         ;;
     esac