stpcpy is from posix-2008, not the gnu/dammit project.  See:

  http://pubs.opengroup.org/onlinepubs/9699919799/functions/stpcpy.html

Needing to #define __ALL_HAIL_RICHARD_STALLMAN in order to get a posix
function is just _sad_.

diff --git a/include/string.h b/include/string.h
index f11a726..73534cb 100644
--- a/include/string.h
+++ b/include/string.h
@@ -416,9 +416,7 @@ extern char *strsep (char **__restrict __stringp,
 		     __const char *__restrict __delim)
      __THROW __nonnull ((1, 2));
 libc_hidden_proto(strsep)
-#endif
 
-#ifdef	__USE_GNU
 /* Compare S1 and S2 as strings holding name & indices/version numbers.  */
 extern int strverscmp (__const char *__s1, __const char *__s2)
      __THROW __attribute_pure__ __nonnull ((1, 2));