--- src/Makefile.am.orig	2023-10-07 16:13:36 UTC
+++ src/Makefile.am
@@ -18,7 +18,7 @@ parse.c: parse.peg
 # _DARWIN_C_SOURCE is for NI_MAXHOST on OS X
 # _XOPEN_SOURCE is for struct sigaction
 # _GNU_SOURCE is for h_errno and gethostbyname-related macros
-___rinetd_CFLAGS = -std=c99 -D_POSIX_C_SOURCE=200809L \
+___rinetd_CFLAGS = -std=c99 \
                    -D_XOPEN_SOURCE -D_GNU_SOURCE -D_DARWIN_C_SOURCE \
                    -Wall -Wextra -Wwrite-strings