ldso: fix USE_TLS check

this was causing tls symbols to leak into non-tls builds

Signed-off-by: Austin Foxley <austinf@cetoncorp.com>

ldso/include/ldso.h

@@ -72,7 +72,7 @@ extern char *_dl_ldsopath;             /* Where the shared lib loader was found
 extern const char *_dl_progname;       /* The name of the executable being run */
 extern size_t _dl_pagesize;            /* Store the page size for use later */
 
-#ifdef USE_TLS
+#if defined(USE_TLS) && USE_TLS
 extern void _dl_add_to_slotinfo (struct link_map  *l);
 extern void ** __attribute__ ((const)) _dl_initial_error_catch_tsd (void);
 #endif