Index: include/time.h
===================================================================
--- include/time.h
+++ include/time.h
@@ -207,9 +207,13 @@
 #include <xlocale/_time.h>
 #endif
 
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \
+    (defined(cplusplus) && cplusplus >= 201703) || \
+    defined(__WANT_TIMESPEC_GET)
 /* ISO/IEC 9899:201x 7.27.2.5 The timespec_get function */
 #define TIME_UTC	1	/* time elapsed since epoch */
 int timespec_get(struct timespec *ts, int base);
+#endif
 
 __END_DECLS
 
Index: lib/libc/gen/timespec_get.c
===================================================================
--- lib/libc/gen/timespec_get.c
+++ lib/libc/gen/timespec_get.c
@@ -33,6 +33,7 @@
 __RCSID("$NetBSD: timespec_get.c,v 1.2 2016/10/04 12:48:15 christos Exp $");
 __FBSDID("$FreeBSD$");
 
+#define __WANT_TIMESPEC_GET
 #include <time.h>
 
 /* ISO/IEC 9899:201x 7.27.2.5 The timespec_get function */