re PR libstdc++/48933 (Infinite recursion in tr1/cmath functions with complex parameters)

re PR libstdc++/48933 (Infinite recursion in tr1/cmath functions with complex parameters)

2011-05-09  Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/48933
	* include/c_global/cmath (acosh, asinh, atanh, cbrt, copysign,
	erf, erfc, exp2, expm1, fdim, fma, fmax, hypot, ilogb, lgamma,
	llrint, llround, log1p, log2, logb, lrint, lround, nearbyint,
	nextafter, nexttoward, remainder, remquo, rint, round, scalbln,
	scalbn, tgamma, trunc): Use __enable_if on the return type.
	* include/tr1/cmath: Likewise.
	* testsuite/26_numerics/headers/cmath/overloads_c++0x_neg.cc: New.
	* testsuite/tr1/8_c_compatibility/cmath/overloads_neg.cc: Likewise.

From-SVN: r173574