SDL_mixer: update for warning flags in watcom makefile.

From 2f54a8ab312c75c90ad55f4ea1ee26d9889a712b Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Wed, 29 Dec 2021 23:55:24 +0300
Subject: [PATCH] update for warning flags in watcom makefile.

---
 Makefile.os2 | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Makefile.os2 b/Makefile.os2
index 0337a014..d2ffbd08 100644
--- a/Makefile.os2
+++ b/Makefile.os2
@@ -62,6 +62,8 @@ LIBS = SDL2.lib
 CFLAGS_BASE = -bt=os2 -d0 -q -bm -5s -fp5 -fpi87 -sg -oteanbmier -ei -j
 # warnings:
 CFLAGS_BASE+= -wx
+# newer OpenWatcom versions enable W303 by default
+CFLAGS_BASE+= -wcd=303
 # include paths:
 CFLAGS_BASE+= -Iinclude -Isrc -I"src/codecs" -I"src/codecs/timidity" $(DEPS_INC)
 CFLAGS_BASE+= -I"$(%WATCOM)/h/os2" -I"$(%WATCOM)/h"