stor-layout.c (place_field): Handle alignment of whole structures when MSVC compatible bitfields are involved.

        * stor-layout.c (place_field): Handle alignment of whole
        structures when MSVC compatible bitfields are involved.
        Change method of computing location of MS bitfields to
        be compatible with #pragma pack(n).

        * tree.h (record_layout_info): Add new field
        remaining_in_alignment.

        * doc/tm.texi: (TARGET_MS_BITFIELD_LAYOUT_P): Update.
        (pragma pack): Add paragraph on MSVC bitfield packing.

Co-Authored-By: Donn Terry <donnte@microsoft.com>

From-SVN: r57281