diff --git a/configure/os/CONFIG_SITE.Common.darwin-x86 b/configure/os/CONFIG_SITE.Common.darwin-x86
index 7aad1537e..f215c8e5e 100644
--- a/configure/os/CONFIG_SITE.Common.darwin-x86
+++ b/configure/os/CONFIG_SITE.Common.darwin-x86
@@ -10,14 +10,14 @@
 #   i386
 #   x86_64  - Needs MacOS 10.4 with the Universal SDK, or 10.5 and later
 
-ARCH_CLASS = i386
-#ARCH_CLASS = x86_64
+#ARCH_CLASS = i386
+ARCH_CLASS = x86_64
 #ARCH_CLASS = i386 x86_64
 
 #
-# Uncomment the followings lines to build with CLANG instead of GCC.
+# Comment out the followings 3 lines to build with GCC instead of CLANG.
 #
-#CC             = clang
-#CCC            = clang++
-#GNU_LDLIBS_YES =
+CC  = clang
+CCC = clang++
+GNU = NO
 
diff --git a/documentation/RELEASE_NOTES.html b/documentation/RELEASE_NOTES.html
index 3c5ba6836..47babb91b 100644
--- a/documentation/RELEASE_NOTES.html
+++ b/documentation/RELEASE_NOTES.html
@@ -13,6 +13,13 @@
 
 <!-- Insert new items immediately below here ... -->
 
+<h4>MacOS build defaults changed</h4>
+
+<p>The default build settings for darwin-x86 targets have been changed to match
+the latest version of XCode; see configure/os/CONFIG_SITE.Common.darwin-x86
+if you need to revert back to building with GCC or to include the i386 CPU
+architecture.</p>
+
 <h4>Build problem with db dependencies</h4>
 
 <p>The dependency output for .db and .acf files created by makeDbDepends.pl did