1.1--- a/lisp/std/os.lisp	Mon Aug 12 18:32:35 2024 -0400
     1.2+++ b/lisp/std/os.lisp	Mon Aug 12 21:16:14 2024 -0400
     1.3@@ -26,3 +26,12 @@
     1.4                                         (sb-posix:group-name g)
     1.5                                         (sb-posix:group-mem g))
     1.6                                   r))))
     1.7+
     1.8+(defmacro with-umask (mask &body body)
     1.9+  "Temporarily set the system-wide umask for the extent of BODY."
    1.10+  (with-gensyms (umask)
    1.11+    `(let ((,umask (sb-posix:umask ,mask)))
    1.12+       (unwind-protect (progn ,@body)
    1.13+         (sb-posix:umask ,umask)))))
    1.14+
    1.15+;; (with-umask #o22 nil)