--- unistd.in.h	2017-05-15 19:05:30.449063823 +0200
+++ unistd.in.h.new	2017-05-15 19:14:39.145268786 +0200
@@ -141,7 +141,11 @@
 
 
 /* Get getopt(), optarg, optind, opterr, optopt.  */
-#if @GNULIB_GETOPT_POSIX@ && @GNULIB_UNISTD_H_GETOPT@ && !defined _GL_SYSTEM_GETOPT
+/* Also, don't include <getopt.h> inside libgettextpo, because we use
+   the getopt module only in gettext-tools/gnulib-lib/, not in
+   gettext-tools/libgettextpo/, but there is only a single
+   GNULIB_UNISTD_H_GETOPT variable for both.  */
+#if @GNULIB_GETOPT_POSIX@ && @GNULIB_UNISTD_H_GETOPT@ && !defined GTPO_CONFIG_H && !defined _GL_SYSTEM_GETOPT
 # include <getopt-cdefs.h>
 # include <getopt-pfx-core.h>
 #endif