Change the gnulib snapshot basename to avoid distdir conflicts.

Author: jmillikin

bison/internal/gnulib/gnulib.bzl

@@ -22,7 +22,7 @@ load(
 _GNULIB_VERSION = "788db09a9f88abbef73c97e8d7291c40455336d8"
 _GNULIB_SHA256 = "4350696d531852118f3735a0e2d1091746388392c27d582f0cc241b6a39fe493"
 
-_URL_BASE = "github.com/jmillikin/rules_bison/releases/download/v0.1/gnulib-{}.tar.xz".format(_GNULIB_VERSION)
+_URL_BASE = "github.com/jmillikin/rules_bison/releases/download/v0.1/bison-gnulib-{}.tar.xz".format(_GNULIB_VERSION)
 
 _GNULIB_URLS = [
     "https://mirror.bazel.build/" + _URL_BASE,