wrappers: site: add hurd-gnu

These are mostly needed because autoconf before 1a449f4d791f15d9f16fa00dace90e25530f1725
only looked for *-gnu*, not gnu* in the os field of the tuple.

Copy linux and prune some bits out. I've not added hurd by itself given
only glibc supports it and it's not clear what a non-glibc hurd would
look like.

Signed-off-by: Sam James <sam@gentoo.org>

Author: thesamesam

wrappers/site/hurd-gnu

@@ -0,0 +1,9 @@
+ac_cv_func_calloc_0_nonnull=yes
+enable_malloc0returnsnull=yes
+ac_cv_func_realloc_0_nonnull=yes
+ac_cv_func_malloc_0_nonnull=yes
+gl_cv_func_strcasecmp_works=yes
+
+ac_cv_buggy_getaddrinfo=no
+ac_cv_file__dev_ptmx=no
+ac_cv_file__dev_ptc=no