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

@@ -228,10 +228,11 @@
 
 /*
  * defined in ucontext.s
  */
 extern int __getcontext(ucontext_t *);
+extern int __getcontext_extd(ucontext_t *);
 
 /*
  * defined in door.s
  */
 extern int __door_info(int, door_info_t *);

@@ -344,10 +345,16 @@
 extern size_t mbrtowc_nz_l(wchar_t *_RESTRICT_KYWD, const char *_RESTRICT_KYWD,
     size_t, mbstate_t *_RESTRICT_KYWD, locale_t);
 extern size_t mbrtowc_nz(wchar_t *_RESTRICT_KYWD, const char *_RESTRICT_KYWD,
     size_t, mbstate_t *_RESTRICT_KYWD);
 
+/*
+ * defined in getauxv.c.
+ */
+extern long ___getauxval(int);
+extern void *___getauxptr(int);
+
 #ifdef  __cplusplus
 }
 #endif
 
 #endif /* _LIBC_H */