patch 9.1.0023: xxd: few problems with EBCDIC for z/OS (MVS)

Problem:  xxd: few problems with EBCDIC for z/OS (MVS)
Solution: Fix xxd build and support ASCII and UTF-8 on z/OS (MVS)
          natively, add MVS guard checks with __CHARSET_LIB,
          support $LIBS in the Makefile
          (Igor Todorovski)

related: #13821

Signed-off-by: Igor Todorovski <itodorov@ca.ibm.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/xxd/Makefile b/src/xxd/Makefile
index 97bbcc7..d08af7a 100644
--- a/src/xxd/Makefile
+++ b/src/xxd/Makefile
@@ -1,7 +1,7 @@
 # The most simplistic Makefile
 
 xxd: xxd.c
-	$(CC) $(CFLAGS) $(LDFLAGS) -DUNIX -o xxd xxd.c
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -DUNIX -o xxd xxd.c $(LIBS)
 
 clean:
 	rm -f xxd xxd.o