Make allocate with source work, some more offset fixes for implied this_image().

Make allocate with source work, some more offset fixes for implied this_image().

gcc/fortran/ChangeLog:

	* options.c (gfc_post_options): Always set flag_debug_aux_vars for
	shared coarrays.
	* resolve.c (gfc_expr_to_initialize): Set extra dimensions to
	DIMEN_THIS_IMAGE.
	* trans-array.c (cas_add_strides): Re-introduce.
	(cas_add_this_image_offset): Rename add_lbound to
	correct_full_offset, use cas_add_strides.

gcc/testsuite/ChangeLog:

	* gfortran.dg/caf-shared/alloc_coarray_with_source_1.f90: New test.
	* gfortran.dg/caf-shared/cobounds_torture_1.f90: New test.
	* gfortran.dg/caf-shared/cobounds_torture_2.f90: New test.
	* gfortran.dg/caf-shared/cobounds_torture_3.f90: New test.