Tiger does not have the _DARWIN_C_SOURCE override to enable chunks of headers
when _POSIX_C_SOURCE is defined, so we have to specifically remove the
_POSIX_C_SOURCE from these files for Tiger builds to succeed.

--- src/sleep.c.orig	2020-04-06 15:21:04.000000000 -0500
+++ src/sleep.c	2020-05-15 07:56:47.000000000 -0500
@@ -33,7 +33,9 @@
 */
 
 #include "config.h"
+#if (__APPLE__ && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050)
 #define _POSIX_C_SOURCE 200112L
+#endif
 
 #include <errno.h>
 #include <time.h>
--- src/tcp.c.orig	2020-04-06 15:21:04.000000000 -0500
+++ src/tcp.c	2020-05-15 07:55:17.000000000 -0500
@@ -40,7 +40,9 @@
 
 /* TCP control file */
 
+#if (__APPLE__ && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050)
 #define _POSIX_C_SOURCE 200112L
+#endif
 
 #include "config.h"
 #include <sys/types.h>