* security.cc: Change some formatting.

* include/cygwin/version.h: Bump API minor version.

        * cygheap.h (class cygheap_user): Add member groups.
        * security.h (class cygsidlist): Add members type and maxcount,
        methods position, addfromgr, alloc_sids and free_sids and
        operator+= (const PSID psid). Modify contains () to call
        position () and optimize add () to use maxcount.
        (class user_groups): Create.
        Update declarations of verify_token and create_token.
        * security.cc (cygsidlist::alloc_sids): New.
        (cygsidlist::free_sids): New.
        (get_token_group_sidlist): Create from get_group_sidlist.
        (get_initgroups_sidlist): Create from get_group_sidlist.
        (get_group_sidlist): Suppress.
        (get_setgroups_sidlist): Create.
        (verify_token): Modify arguments. Add setgroups case.
        (create_token): Modify arguments. Call get_initgroups_sidlist and
        get_setgroups_sidlist as needed. Set SE_GROUP_LOGON_ID from auth_pos
        outside of the loop. Rename the various group sid lists consistently.
        * syscalls.cc (seteuid32): Modify to use cygheap->user.groups.
        (setegid32): Call cygheap->user.groups.update_pgrp.
        * grp.cc (setgroups): Create.
        (setgroups32): Create.
        * uinfo.cc (internal_getlogin): Initialize and update user.groups.pgsid.
        * cygwin.din: Add setgroups and setgroups32.

winsup/cygwin/cygheap.h

@@ -113,6 +113,7 @@ public:
   __gid32_t orig_gid;      /* Ditto */
   __uid32_t real_uid;      /* Remains intact on seteuid, replaced by setuid */
   __gid32_t real_gid;      /* Ditto */
+  user_groups groups;      /* Primary and supp SIDs */
 
   /* token is needed if set(e)uid should be called. It can be set by a call
      to `set_impersonation_token()'. */