cmath (pow(float, int), [...]): Do not define in C++0x mode, per DR 550.

2008-05-26  Paolo Carlini  <paolo.carlini@oracle.com>

	* include/c_global/cmath (pow(float, int), pow(double, int),
	pow(long double, int)): Do not define in C++0x mode, per DR 550.
	* include/tr1_impl/cmath (pow): Do not bring in unconditionally
	from namespace std.
	* include/tr1/cmath (pow(double, double), pow(float, float),
	pow(long double, long double), pow(_Tp, _Up)): Define.
	* include/tr1/complex (pow): Do not bring in from namespace std.
	(pow(const std::complex<_Tp>&, int), pow(const std::complex<_Tp>&,
	const _Tp&), pow(const _Tp&, const std::complex<_Tp>&),
	pow(const std::complex<_Tp>&, const std::complex<_Tp>&)): Define.
	* include/tr1_impl/complex (pow(const std::complex<_Tp>&,
	const _Up&), pow(const _Tp&, const std::complex<_Up>&),
	pow(const std::complex<_Tp>&, const std::complex<_Up>&)): Always
	define.
	* doc/xml/manual/intro.xml: Add an entry for DR 550.
	* testsuite/26_numerics/headers/cmath/dr550.cc: New.
	* testsuite/tr1/8_c_compatibility/cmath/overloads.cc: Adjust.

From-SVN: r135955