--- m4/malloc.m4.orig	2020-06-03 23:04:44.000000000 +1000
+++ m4/malloc.m4	2020-07-31 00:06:44.156408000 +1000
@@ -30,7 +30,7 @@
        [ac_cv_func_malloc_0_nonnull=no],
        [case "$host_os" in
           # Guess yes on platforms where we know the result.
-          *-gnu* | gnu* | *-musl* | freebsd* | netbsd* | openbsd* \
+          *-gnu* | gnu* | *-musl* | bsdsunix* | freebsd* | netbsd* | openbsd* \
           | hpux* | solaris* | cygwin* | mingw*)
             ac_cv_func_malloc_0_nonnull="guessing yes" ;;
           # If we don't know, obey --enable-cross-guesses.