Adding posix signal handling.

posix/autoboot.fs

@@ -13,12 +13,12 @@
 \ limitations under the License.
 
 ( Include first argument if any )
-internals definitions
+posix also internals definitions
 : autoexec
    ( Open passed file if any. )
-   argc 2 >= if 1 argv included exit then
+   argc 2 >= if 1 argv ['] included catch if 1 sysexit then exit then
    ( Open remembered file if any. )
    ['] revive catch drop
 ;
 ' autoexec ( leave on dstack for fini.fs )
-forth definitions
+only forth definitions