fix install script to work with sys/asan.sh

sys/asan.sh

@@ -7,7 +7,7 @@ ${CC} ${CFLAGS} ${LDFLAGS} -o .a.out .a.c
 RET=$?
 rm -f .a.out .a.c
 if [ $RET != 0 ]; then
-	echo "Your compiler doesn't supports ASAN."
+	echo "Your compiler doesn't support ASAN."
 	exit 1
 fi
 exec sys/install.sh $*

sys/install.sh

@@ -7,7 +7,7 @@ gmake --help >/dev/null 2>&1
 [ -z "${INSTALL_TARGET}" ] && INSTALL_TARGET=symstall
 
 # find root
-cd `dirname $PWD/$0` ; cd ..
+cd $(dirname $0) ; cd ..
 
 # update
 if [ "$1" != "--without-pull" ]; then