ggc-page.c (USING_MALLOC_PAGE_GROUPS): New; set if not using mmap.

ggc-page.c (USING_MALLOC_PAGE_GROUPS): New; set if not using mmap.

        * ggc-page.c (USING_MALLOC_PAGE_GROUPS): New; set if not using mmap.
        (struct page_entry): Add group member.
        (struct page_group): New.
        (struct globals): Add page_groups member.
        (alloc_anon): Only define for using mmap; remove valloc call.
        (page_group_index): New.
        (set_page_group_in_use): New.
        (clear_page_group_in_use): New.
        (alloc_page): Implement USING_MALLOC_PAGE_GROUPS.
        (free_page, release_pages): Likewise.
        * configure.in (with-gc): Default to ggc-page always.

From-SVN: r38992