Remove unnecessary warning flags in Makefile.

From: Seth M. Price <sprice623@aol.com>

--- a/vt100/Makefile
+++ b/vt100/Makefile
@@ -9,11 +9,10 @@ endif
 #For clang: CFLAGS=-Ofast
 check: vt100 ../test/test.sh
 	cd ..; sh test/test.sh
-WARN=-Wall -Wno-unused-parameter -Wno-parentheses -Wno-unused-result
+WARN=
 SRC=main.c cpu.c sys.c ddt.c pusart.c \
 	nvr.c keyboard.c video.c rom.c sound.c render.c \
 	../common/sdl.c ../common/opengl.c ../common/event.c \
 	../common/logger.c ../common/pty.c
 DEPS=`sdl2-config --libs --cflags` -lSDL2_image $(LDFLAGS)
 vt100: $(SRC) Makefile vt100.h ../common/xsdl.h ../common/opengl.h