bunpen: preserve environment across exec boundary

pkgs/additional/bunpen/main.ha

@@ -16,7 +16,7 @@ fn do_exec(path: str, args: []str) (os::exec::error | void) = {
     log::printfln("exec ({}): {}", path, joined);
   };
 
-  rtext::check_error("exec", rtext::execve(path, args));
+  rtext::check_error("exec", rtext::execve(path, args, os::getenvs()));
 
   // XXX: os::exec::exec offers no way to preserve argv0, but it does
   // work if you don't care about that:

pkgs/additional/bunpen/rtext/exec.ha

@@ -12,8 +12,7 @@ export fn execve(path: str, argv: []str, envp: []str = []) (rt::errno | void) =
     make_cstr(&path_buf, path): uintptr: u64,
     // XXX: this "leaks" the c arrays, but not much can be done about that
     to_cstr_array(argv): *[*]nullable *const c::char: uintptr: u64,
-    0,
-    // to_cstr_array(envp): *[*]nullable *const c::char: uintptr: u64,
+    to_cstr_array(envp): *[*]nullable *const c::char: uintptr: u64,
   )?;
 };