Per suggestion from Eric Norum, went from one initial extension set

to multiple.  This lets the stack check extension be installed
at system initialization time and avoids the BSP having to
even know about its existence.

c/src/lib/libbsp/unix/posix/startup/bspstart.c

@@ -36,10 +36,6 @@
 
 #include <rtems/libio.h>
 
-#ifdef STACK_CHECKER_ON
-#include <stackchk.h>
-#endif
-
 extern rtems_configuration_table  Configuration;
 
 /*
@@ -153,15 +149,6 @@ bsp_pretasking_hook(void)
 {
     bsp_libc_init();
 
-#ifdef STACK_CHECKER_ON
-    /*
-     *  Initialize the stack bounds checker
-     *  We can either turn it on here or from the app.
-     */
-
-    Stack_check_Initialize();
-#endif
-
 #ifdef RTEMS_DEBUG
     rtems_debug_enable( RTEMS_DEBUG_ALL_MASK );
 #endif