Darwin, D: Fix D bootstrap, include tm-dwarf2.h.

After r12-4432-g7bfe7d634f60b0a9 Darwin fails to bootstrap with D
enabled since there is no definition of either DWARF2_DEBUG_INFO or
PREFERRED_DEBUGGING_TYPE.

Fixed here by adding the tm-dwarf2.h file to tm_d_file for Darwin.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>

gcc/ChangeLog:

	* config.gcc: Add tm-dwarf2.h to tm_d-file.
1 file changed