gnulib: update

* README-hacking: Commit before bootstrapping.
* bootstrap.conf: gnulib_mk is no longer defined by bootstrap.
* bootstrap, gnulib, lib/.gitignore, m4/.gitignore: Update/regen.

lib/.gitignore

@@ -117,7 +117,6 @@
 /malloc.c
 /malloca.c
 /malloca.h
-/malloca.valgrind
 /math.c
 /math.h
 /math.in.h
@@ -229,7 +228,6 @@
 /sys_ioctl.in.h
 /sys_socket.in.h
 /sys_stat.in.h
-/sys_time.in.h
 /sys_types.in.h
 /sys_wait.in.h
 /sysexits.in.h
@@ -276,3 +274,5 @@
 /xsize.h
 /xstrndup.c
 /xstrndup.h
+/stat-time.c
+/stat-time.h