Hurd compat fixes. Mostly dealing with absent PATH_MAX

Signed-off-by: Jérémie Koenig <jk@jk.fr.eu.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/libbb/xreadlink.c b/libbb/xreadlink.c
index 8d232f1..faa0e16 100644
--- a/libbb/xreadlink.c
+++ b/libbb/xreadlink.c
@@ -100,18 +100,16 @@
 	return buf;
 }
 
-/* UNUSED */
-#if 0
 char* FAST_FUNC xmalloc_realpath(const char *path)
 {
 #if defined(__GLIBC__) && !defined(__UCLIBC__)
 	/* glibc provides a non-standard extension */
+	/* new: POSIX.1-2008 specifies this behavior as well */
 	return realpath(path, NULL);
 #else
 	char buf[PATH_MAX+1];
 
-	/* on error returns NULL (xstrdup(NULL) ==NULL) */
+	/* on error returns NULL (xstrdup(NULL) == NULL) */
 	return xstrdup(realpath(path, buf));
 #endif
 }
-#endif