Restore Saved_State/Halt_State when a longjmp happens

this fixes CC#2190, which is illustrated by:

attempt [; this sets Saved_State
	catch/quit [ ;this calls Try_Block_Halt and sets Halt_State
		print x ; this causes an error, and calls
			;"longjmp(*State_State)", which invalidates
			; Halt_State above.
	]
]
load %./ ;Just tries to fill up the C stack and messes up "Halt_State".
halt ; Jumps to the invalid "Halt_State", and crashes

or

catch/quit [ ;sets Halt_State
    attempt [ ;sets Saved_State
        quit ; jumps to Halt_State, and invalidates "Saved_State"
    ]
]
print x ; Causes a jump to the invalid "Saved_State"
[Linux] Don't catch SIGSEGV

Usually handling of this signal causes another SIGSEGV, which ends up an
endless recursion.
Merge branch 'atronix' into call-atronix

Conflicts:
	src/core/c-do.c
Add a native 'access-os'

It's almost like what's in R2, with the addition of 'euid and 'egid, and
additional signal number to kill the process:

access-os/set 'pid [2123 9] ;send a signal 9 (SIGKILL) to process 2123
Add OS_ENA and now error out for it

Just try to mimic R2
Fix the regression

commit 630945070eaa4ae4310f53d9dbf34c30db712a21
Author: Shixin Zeng <szeng@atronixengineering.com>
Date:   Wed Dec 3 16:28:53 2014 -0500

    Add UTF-16LE/BE codec for strings

broke the code:

>> decode 'text #{68}

and thus broke https scheme
Merge branch 'atronix' into call-atronix

Conflicts:
	src/boot/words.r