diff --git a/Source/GNUmakefile b/Source/GNUmakefile
index 8a70e71c2..5332dd884 100644
--- a/Source/GNUmakefile
+++ b/Source/GNUmakefile
@@ -199,6 +199,8 @@ NSData.m \
 NSDate.m \
 NSDateFormatter.m \
 NSDebug.m \
+NSDecimal.m \
+NSDecimalNumber.m \
 NSDictionary.m \
 NSDistantObject.m \
 NSDistributedLock.m \