d: Split up d-frontend.cc into multiple parts.

d: Split up d-frontend.cc into multiple parts.

gcc/d/ChangeLog:

	* Make-lang.in (D_OBJS): Add d-compiler.o, d-ctfloat.o, d-port.o.
	* d-frontend.cc (Port::memicmp): Move to d-port.cc.
	(Port::strupr): Likewise.
	(Port::isFloat32LiteralOutOfRange): Likewise.
	(Port::isFloat64LiteralOutOfRange): Likewise.
	(Port::readwordLE): Likewise.
	(Port::readwordBE): Likewise.
	(Port::readlongLE): Likewise.
	(Port::readlongBE): Likewise.
	(Port::valcpy): Likewise.
	(CTFloat::fabs): Move to d-ctfloat.cc.
	(CTFloat::ldexp): Likewise.
	(CTFloat::isIdentical): Likewise.
	(CTFloat::isNaN): Likewise.
	(CTFloat::isSNaN): Likewise.
	(CTFloat::isInfinity): Likewise.
	(CTFloat::parse): Likewise.
	(CTFloat::sprint): Likewise.
	(CTFloat::hash): Likewise.
	(Compiler::genCmain): Move to d-compiler.cc.
	(Compiler::paintAsType): Likewise.
	(Compiler::loadModule): Likewise.
	* d-compiler.cc: New file.
	* d-ctfloat.cc: New file.
	* d-port.cc: New file.