New --reexec option.

This helps with setuid hash bang scripting on Mac OS,
and other plaforms where the interpreter executed out
of a hash bang script runs with orinary privilege,
even if marked setuid.

* sysif.c (exec_wrap): Static function turns extern.

* sysif.h (exec-wrap): Declared.

* txr.1: Documented --reexec. Added notes about setuid under
Hash Bang Support.

* txr.c (help): List --reexec option.
(txr_main): Implement --reexec option.

1 files changed, 3 insertions, 0 deletions

diff --git a/sysif.h b/sysif.h
index 093e4152..62712387 100644
--- a/sysif.h
+++ b/sysif.h
@@ -43,6 +43,9 @@ typedef long off_t;
 #endif
 
 val getenv_wrap(val name);
+#if HAVE_FORK_STUFF
+val exec_wrap(val file, val args_opt);
+#endif
 #if HAVE_SYS_STAT
 struct stat;
 val stat_to_struct(struct stat st);