[libstdc++] fix alpha build

[Andreas Tobler]

Richard Henderson wrote:
> In the alpha port, __alpha is defined to 1, which causes 
> a number of parse errors.

This one is missing, I'll commit as obvious.

Andreas

2007-04-01  Andreas Tobler  <a.tobler@schweiz.org>

	* include/tr1/poly_laguerre.tcc: Missing s/__alpha/__alpha1, line 278.

Index: include/tr1/poly_laguerre.tcc
===================================================================
--- include/tr1/poly_laguerre.tcc       (revision 123409)
+++ include/tr1/poly_laguerre.tcc       (working copy)
@@ -275,7 +275,7 @@
        else if (__n > 10000000 && _Tp(__alpha1) > -_Tp(1)
              && __x < _Tp(2) * (_Tp(__alpha1) + _Tp(1)) + _Tp(4 * __n))
          return __poly_laguerre_large_n(__n, __alpha1, __x);
-      else if (_Tp(__alpha) >= _Tp(0)
+      else if (_Tp(__alpha1) >= _Tp(0)
             || (__x > _Tp(0) && _Tp(__alpha1) < -_Tp(__n + 1)))
          return __poly_laguerre_recursion(__n, __alpha1, __x);
        else