Make sh(1) gprof(1)-able.
_exit(2) is directly used because sh uses vfork(2).
Thanks to Christos Zoulas.

Index: trap.c
===================================================================
RCS file: /cvsroot/src/bin/sh/trap.c,v
retrieving revision 1.37
diff -u -p -r1.37 trap.c
--- trap.c	22 Aug 2015 12:12:47 -0000	1.37
+++ trap.c	15 Dec 2015 20:04:05 -0000
@@ -479,6 +479,8 @@ l1:   handler = &loc2;			/* probably unn
 #if JOBS
 	setjobctl(0);
 #endif
-l2:   _exit(status);
+l2:   
+	_mcleanup();
+	_exit(status);
 	/* NOTREACHED */
 }
Index: trap.h
===================================================================
RCS file: /cvsroot/src/bin/sh/trap.h,v
retrieving revision 1.22
diff -u -p -r1.22 trap.h
--- trap.h	22 Aug 2015 12:12:47 -0000	1.22
+++ trap.h	15 Dec 2015 20:04:05 -0000
@@ -44,3 +44,5 @@ void dotrap(void);
 void setinteractive(int);
 void exitshell(int) __dead;
 int lastsig(void);
+
+extern void _mcleanup(void);