New AIX template failures

[David Edelsohn]

FAIL: 27_io/basic_istream/sentry/char/3983-fstream.cc (test for excess errors)
Excess errors:
ld: 0711-317 ERROR: Undefined symbol: std::basic_filebuf<unsigned char, std::char_traits<unsigned char> >::_S_pback_size

FAIL: 27_io/basic_ostream/sentry/char/3983-fstream.cc (test for excess errors)
Excess errors:
ld: 0711-317 ERROR: Undefined symbol: std::basic_filebuf<unsigned char, std::char_traits<unsigned char> >::_S_pback_size

FAIL: 27_io/manipulators/standard/char/2.cc (test for excess errors)
Excess errors:
ld: 0711-317 ERROR: Undefined symbol: .double std::__cmath_power<double>(double, unsigned)
ld: 0711-317 ERROR: Undefined symbol: .float std::__cmath_power<float>(float, unsigned)
ld: 0711-317 ERROR: Undefined symbol: .long double std::__cmath_power<long double>(long double, unsigned)
ld: 0711-317 ERROR: Undefined symbol: .std::valarray<unsigned long>::valarray[in-charge]()