random.tcc: Use __builtin_isfinite instead of std::isfinite.

2016-01-15  Steve Ellcey  <sellcey@imgtec.com>

	* include/ext/random.tcc: Use __builtin_isfinite instead of
	std::isfinite.

From-SVN: r232452

libstdc++-v3/ChangeLog

+2016-01-15  Steve Ellcey  <sellcey@imgtec.com>
+
+	* include/ext/random.tcc: Use __builtin_isfinite instead of
+	std::isfinite.
+
 2016-01-15  Jonathan Wakely  <jwakely@redhat.com>
 
 	* include/bits/std_mutex.h: Fix Doxygen @file name.

libstdc++-v3/include/ext/random.tcc

@@ -1570,7 +1570,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 			      return __t; });
 	      __norm = std::sqrt(__sum);
 	    }
-	  while (__norm == _RealType(0) || ! std::isfinite(__norm));
+	  while (__norm == _RealType(0) || ! __builtin_isfinite(__norm));
 
 	  std::transform(__ret.begin(), __ret.end(), __ret.begin(),
 			 [__norm](_RealType __val){ return __val / __norm; });