Fix build on VS8.
diff --git a/PC/VS8.0/pythoncore.vcproj b/PC/VS8.0/pythoncore.vcproj
index 4c19e40..9edd99e 100644
--- a/PC/VS8.0/pythoncore.vcproj
+++ b/PC/VS8.0/pythoncore.vcproj
@@ -1091,7 +1091,7 @@
 				>
 			</File>
 			<File
-				RelativePath="..\..\Modules\datetimemodule.c"
+				RelativePath="..\..\Modules\_datetimemodule.c"
 				>
 			</File>
 			<File