Cosmetic fix: the file uses explicit STRUCTURE-REFs for all

references to THREADS-INTERNAL except one.  Make that one reference
into a STRUCTURE-REF also.

scsh/sighandlers.scm

@@ -175,7 +175,7 @@
 	  (set-interrupt-handler 
 	   i
 	   #t))))
-  (let ((scsh-initial-thread  (current-thread)))
+  (let ((scsh-initial-thread  ((structure-ref threads-internal current-thread))))
     (if (not (eq? (thread-name scsh-initial-thread)
 		  'scsh-initial-thread))
 	(error "sighandler did not find scsh-initial-thread, but"