Avoid pointless warning when building experimental code anyway

Change-Id: Ied9a4fb4eed0a7fda8e6b1bd03a3dbc476797587

configure.ac

@@ -2732,6 +2732,7 @@ if test "$_os" = "Darwin"; then
         esac
     fi
 
+    if test "$BITNESS_OVERRIDE" == ""; then
         case "$with_macosx_version_min_required" in
         10.4)
             case "$with_macosx_sdk" in
@@ -2748,6 +2749,7 @@ if test "$_os" = "Darwin"; then
             add_warning "Building with a minimum version requirement > 10.4 breaks 10.4 compatibility. Do not use for deliverable build"
             ;;
         esac
+    fi
 
     # If no CC and CXX environment vars, try to guess where the compiler is
     if test -z "$save_CC"; then