diff --git a/include/extern.h b/include/extern.h
index eafc34c92..64026008e 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1,4 +1,4 @@
-/* NetHack 5.0	extern.h	$NHDT-Date: 1770949988 2026/02/12 18:33:08 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1523 $ */
+/* NetHack 5.0	extern.h	$NHDT-Date: 1778886716 2026/05/15 15:11:56 $  $NHDT-Branch: NetHack-5.0 $:$NHDT-Revision: 1.1558 $ */
 /* Copyright (c) Steve Creps, 1988.                               */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -693,7 +693,8 @@ extern void free_mgivenname(struct monst *) NONNULLARG1;
 extern void new_oname(struct obj *, int) NONNULLARG1;
 extern void free_oname(struct obj *) NONNULLARG1;
 extern const char *safe_oname(struct obj *) NONNULLARG1;
-extern struct monst *christen_monst(struct monst *, const char *) NONNULLARG1;
+extern struct monst *christen_monst(struct monst *, const char *) NONNULL
+                                                                   NONNULLARG1;
 extern struct obj *oname(struct obj *, const char *, unsigned) NONNULLPTRS;
 extern boolean objtyp_is_callable(int);
 extern int name_ok(struct obj *);
diff --git a/src/options.c b/src/options.c
index f5d24b1b1..0bb1b4b29 100644
--- a/src/options.c
+++ b/src/options.c
@@ -1,4 +1,4 @@
-/* NetHack 5.0	options.c	$NHDT-Date: 1737556914 2025/01/22 06:41:54 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.753 $ */
+/* NetHack 5.0	options.c	$NHDT-Date: 1778886716 2026/05/15 15:11:56 $  $NHDT-Branch: NetHack-5.0 $:$NHDT-Revision: 1.782 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Michael Allison, 2008. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -558,6 +558,7 @@ parseoptions(
         got_match = FALSE;
 
         if (allopt[i].pfx) {
+            assert(allopt[i].name != NULL);
             if (str_start_is(opts, allopt[i].name, TRUE)) {
                 matchidx = i;
                 got_match = pfx_match = TRUE;
diff --git a/sys/unix/unixunix.c b/sys/unix/unixunix.c
index d614f3278..55c173004 100644
--- a/sys/unix/unixunix.c
+++ b/sys/unix/unixunix.c
@@ -1,4 +1,4 @@
-/* NetHack 5.0	unixunix.c	$NHDT-Date: 1711213894 2024/03/23 17:11:34 $  $NHDT-Branch: NetHack-5.0 $:$NHDT-Revision: 1.43 $ */
+/* NetHack 5.0	unixunix.c	$NHDT-Date: 1778886716 2026/05/15 15:11:56 $  $NHDT-Branch: NetHack-5.0 $:$NHDT-Revision: 1.48 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Kenneth Lorber, Kensington, Maryland, 2015. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -370,6 +370,9 @@ int
 child(int wt)
 {
     int f;
+#ifdef CHDIR
+    const char *home = getenv("HOME");
+#endif
 
     suspend_nhwindows((char *) 0); /* also calls end_screen() */
 #ifdef _M_UNIX
@@ -382,7 +385,8 @@ child(int wt)
         (void) setgid(getgid());
         (void) setuid(getuid());
 #ifdef CHDIR
-        (void) chdir(getenv("HOME"));
+        if (home)
+            (void) chdir(home);
 #endif
         return 1;
     }