remove hardcoded O3

Index: configure
--- configure.orig
+++ configure
@@ -541,25 +541,6 @@ fi
 rm -f _testprog _testprog.error _testprog.stdout
 
 
-#  -O optimization for non-debug builds. Try -O and -O3.
-if [ ! z"$DEBUG" = zYES ]; then
-	printf "checking whether -O3 or -O can be used (non-DEBUG build)... "
-	$CC $CFLAGS -O _testprog.c -o _testprog 2> /dev/null
-	if [ -x _testprog ]; then
-		rm -f _testprog
-		$CC $CFLAGS -O3 _testprog.c -o _testprog 2> /dev/null
-		if [ -x _testprog ]; then
-			CFLAGS="-O3 $CFLAGS"
-			printf "yes, -O3\n"
-		else
-			CFLAGS="-O $CFLAGS"
-			printf "yes, -O\n"
-		fi
-	else
-		printf "no\n"
-	fi
-fi
-rm -f _testprog
 
 
 #  -fpeephole