AT_EXECFN is Linux specific

--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -1119,9 +1119,11 @@
 	  case AT_ENTRY:
 	    av->a_un.a_val = *user_entry;
 	    break;
+# ifdef AT_EXECFN	    
 	  case AT_EXECFN:
 	    av->a_un.a_val = (uintptr_t) _dl_argv[0];
 	    break;
+# endif	    
 	  }
 #endif
     }