From 48e61ddfaff09b0a40a18e559117cd06a26cb599 Mon Sep 17 00:00:00 2001
From: Ronald Oussoren <ronaldoussoren@mac.com>
Date: Sun, 22 Nov 2020 02:13:11 +0100
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 00000000000000..008c972e5c6ab0
--- /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 96dcd0dcd5fec1..dfb6e7ef3f0f79 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.$ac_ext
+
         # end of Darwin* tests
         ;;
     esac
diff --git a/configure.ac b/configure.ac
index 18a044629a7853..6c8fd5a3892778 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1931,6 +1931,13 @@ yes)
         EXPORT_MACOSX_DEPLOYMENT_TARGET=''
         AC_MSG_RESULT($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