Self-recover for linux

Compile-time option SELF_RECOVER was implemented for Windows;
add it to unix systems too, with it being on by default when
compiling with the linux hints file.

sys/unix/unixmain.c

@@ -276,6 +276,9 @@ main(int argc, char *argv[])
                 }
             }
         }
+        if (gp.program_state.in_self_recover) {
+            gp.program_state.in_self_recover = FALSE;
+        }
     }
 
     if (!resuming) {