Clean generated *.su file and gitignore them
diff --git a/programs/Makefile b/programs/Makefile
index d09949b..9b01e45 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -298,8 +298,9 @@
 	rm -f $(APPS)
 	-rm -f ssl/ssl_pthread_server$(EXEXT)
 	-rm -f test/cpp_dummy_build$(EXEXT)
+	-rm -f *.su
 else
-	del /S /Q /F *.o *.exe
+	del /S /Q /F *.o *.su *.exe
 endif
 
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