15254 %ymm registers not restored after signal handler
15367 x86 getfpregs() summons corrupting %xmm ghosts
15333 want x86 /proc xregs support (libc_db, libproc, mdb, etc.)
15336 want libc functions for extended ucontext_t
15334 want ps_lwphandle-specific reg routines
15328 FPU_CW_INIT mistreats reserved bit
15335 i86pc fpu_subr.c isn't really platform-specific
15332 setcontext(2) isn't actually noreturn
15331 need <sys/stdalign.h>
Change-Id: I7060aa86042dfb989f77fc3323c065ea2eafa9ad
Conflicts:
    usr/src/uts/common/fs/proc/prcontrol.c
    usr/src/uts/intel/os/archdep.c
    usr/src/uts/intel/sys/ucontext.h
    usr/src/uts/intel/syscall/getcontext.c

@@ -679,10 +679,11 @@
 const   struct systable ctxtable[] = {
 {"getcontext",  2, DEC, NOV, HID, HEX},                         /* 0 */
 {"setcontext",  2, DEC, NOV, HID, HEX},                         /* 1 */
 {"getustack",   2, DEC, NOV, HID, HEX},                         /* 2 */
 {"setustack",   2, DEC, NOV, HID, HEX},                         /* 3 */
+{"getcontext_extd",     2, DEC, NOV, HID, HEX},                         /* 4 */
 };
 #define NCTXCODE        (sizeof (ctxtable) / sizeof (struct systable))
 
 const   struct systable hrttable[] = {
 {"hrtcntl",     5, DEC, NOV, HID, DEC, DEC, HEX, HEX},          /* 0 */