Auto-detect the macios-adr repo to enable any private build logic. (#22240)

Author: rolfbjarne

create-make-config.sh

@@ -33,4 +33,10 @@ if which ccache > /dev/null 2>&1; then
 	echo "Found ccache on the system, enabling it"
 fi
 
+# Detect ADR
+if test -d ../macios-adr; then
+	printf "ENABLE_XAMARIN=1\n" >> "$OUTPUT_FILE"
+	echo "Detected the macios-adr repository, automatically enabled the Xamarin build"
+fi
+
 mv "$OUTPUT_FILE" "$OUTPUT"