gh-36345: ecm: Work around build failure with Xcode 15

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Part of the fix for:
- #36342

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URL: #36345
Reported by: Matthias Köppe
Reviewer(s):

build/pkgs/configure/checksums.ini

@@ -1,4 +1,4 @@
 tarball=configure-VERSION.tar.gz
-sha1=6652d527e5319a54a9ab4e4c2faa48f13afb967d
-md5=156c1701927f83baf70db3f53314bcbe
-cksum=3874404163
+sha1=c6efbc310523cfc3c1f2fa3f86a0761311de6003
+md5=670d28340bbdd4cabaeb3e76a2004dbe
+cksum=2059970385

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-930d65e684b584c6ca664821f008ac205880d857
+8cf728dfa04520d04e7eac3f8e6751eab0c3dde5

build/pkgs/ecm/spkg-install.in

@@ -189,6 +189,12 @@ export CFLAGS # Not exported by 'sage-env'.  LDFLAGS are exported above if
               # necessary.  We currently don't set (or modify) any other
               # environment variables, so don't have to export them here.
 
+# Workaround for build failure with Xcode 15, https://github.com/sagemath/sage/issues/36342
+case "$UNAME" in
+    Darwin*)
+        export gmp_cv_asm_underscore=yes
+        ;;
+esac
 
 ###############################################################################
 # Now configure ECM: