https://github.com/madler/pigz/commit/e1ed230a1599a3cb64c8f5c003cced60e10e3314
https://github.com/madler/pigz/issues/107

From e1ed230a1599a3cb64c8f5c003cced60e10e3314 Mon Sep 17 00:00:00 2001
From: Mark Adler <madler@alumni.caltech.edu>
Date: Sat, 31 Dec 2022 21:28:26 -0800
Subject: [PATCH] Avoid calling memcpy() with a NULL pointer.

This is not permitted by the C99 standard even when the length is
zero. Go figure.
--- a/pigz.c
+++ b/pigz.c
@@ -3414,8 +3414,10 @@ local int outb(void *desc, unsigned char *buf, unsigned len) {
 
         // copy the output and alert the worker bees
         out_len = len;
-        g.out_tot += len;
-        memcpy(out_copy, buf, len);
+        if (len) {
+            g.out_tot += len;
+            memcpy(out_copy, buf, len);
+        }
         twist(outb_write_more, TO, 1);
         twist(outb_check_more, TO, 1);