cmath: workaround compiler glitch 'long double(12)'.
cmath: workaround compiler glitch 'long double(12)'.

	* include/libport/cmath.hxx: Use C cast instead of constructor, as
	some compilers do not like multiple words types constructors.

aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport