[PATCH] replace strerror() usage with threadsafe "%m" format string

strerror() is not threadsafe.  It uses a buffer to build messages of the form
"Unknown error 387689".

syslog() provides a %m format which is equivalent to strerror(errno).
As a GNU extension, this is also accepted by printf and friends.
At least in the current implementation, it is correctly threadsafe.

Signed-off-by: Alan Jenkins <alan-jenkins <at> tuffmail.co.uk>

diff --git a/udev/lib/libudev-ctrl.c b/udev/lib/libudev-ctrl.c
index 7d37074..268ce2d 100644
--- a/udev/lib/libudev-ctrl.c
+++ b/udev/lib/libudev-ctrl.c
@@ -79,7 +79,7 @@ struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socke

 	uctrl->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 	if (uctrl->sock < 0) {
-		err(udev, "error getting socket: %s\n", strerror(errno));
+		err(udev, "error getting socket: %m\n");
 		udev_ctrl_unref(uctrl);
 		return NULL;
 	}
@@ -101,7 +101,7 @@ int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)

 	err= bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 	if (err < 0) {
-		err(uctrl->udev, "bind failed: %s\n", strerror(errno));
+		err(uctrl->udev, "bind failed: %m\n");
 		return err;
 	}