Backport from xs.

xs_io.h

@@ -67,7 +67,7 @@ d_char *xs_read(FILE *f, int *sz)
     }
 
     /* null terminate, just in case it's treated as a string */
-    s = xs_realloc(s, rdsz + 1);
+    s = xs_realloc(s, _xs_blk_size(rdsz + 1));
     s[rdsz] = '\0';
 
     *sz = rdsz;

xs_version.h

@@ -1 +1 @@
-/* a4ce4b2c0c9cd7c40aedd31eb352e3b979de3a17 */
+/* ad1c7ba748725abdecc1f1124d697f9130c49e87 */