Remove dead strlcpy and strlcat declarations

Remove stray references to strlcpy and strlcat that broke builds on
platforms where those functions are part of libc.  Thanks to Karl
Kornel for the report.

NEWS

                        User-Visible wallet Changes
 
+wallet 1.4 (unreleased)
+
+    Remove stray references to strlcpy and strlcat that broke builds on
+    platforms where those functions are part of libc.  Thanks to Karl
+    Kornel for the report.
+
 wallet 1.3 (2016-01-17)
 
     This release adds initial, experimental support for using Active

portable/system.h

@@ -136,12 +136,6 @@ extern void *reallocarray(void *, size_t, size_t);
 #if !HAVE_SETENV
 extern int setenv(const char *, const char *, int);
 #endif
-#if !HAVE_DECL_STRLCAT
-extern size_t strlcat(char *, const char *, size_t);
-#endif
-#if !HAVE_DECL_STRLCPY
-extern size_t strlcpy(char *, const char *, size_t);
-#endif
 
 /* Undo default visibility change. */
 #pragma GCC visibility pop