eliminate use of SHARED macro in __tls_get_addr

this was only a tiny optimization, and static-linked binaries should
not be calling __tls_get_addr anyway since the linker is supposed to
perform relaxation, resulting in use of the local-exec TLS model.

src/thread/__tls_get_addr.c

 #include <stddef.h>
 #include "pthread_impl.h"
+#include "libc.h"
+
+__attribute__((__visibility__("hidden")))
+void *__tls_get_new(size_t *);
 
 void *__tls_get_addr(size_t *v)
 {
 	pthread_t self = __pthread_self();
-#ifdef SHARED
-	__attribute__((__visibility__("hidden")))
-	void *__tls_get_new(size_t *);
 	if (v[0]<=(size_t)self->dtv[0])
 		return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
 	return __tls_get_new(v);
-#else
-	return (char *)self->dtv[1]+v[1]+DTP_OFFSET;
-#endif
 }
+
+weak_alias(__tls_get_addr, __tls_get_new);