Fix:

error: implicitly declaring library function 'strdup' with type 'char *(const char *)' [-Werror,-Wimplicit-function-declaration]
--- Makefile.in.orig	2013-03-04 07:34:37.000000000 -0600
+++ Makefile.in	2024-07-15 06:01:03.000000000 -0500
@@ -149,7 +149,7 @@
 CFLAGS = @CFLAGS@
 CPPFLAGS = @CPPFLAGS@
 CYGPATH_W = @CYGPATH_W@
-DEFS = @DEFS@ -DSYSCONFDIR=\"$(sysconfdir)\" -D_XOPEN_SOURCE=500
+DEFS = @DEFS@ -DSYSCONFDIR=\"$(sysconfdir)\" -D_XOPEN_SOURCE=600
 DEPDIR = @DEPDIR@
 ECHO_C = @ECHO_C@
 ECHO_N = @ECHO_N@