diff -uNr busybox-1.29.3/include/platform.h busybox-1.29.3.mod/include/platform.h
--- busybox-1.29.3/include/platform.h	2018-07-02 14:23:06.000000000 +0300
+++ busybox-1.29.3.mod/include/platform.h	2019-02-08 16:01:14.437858554 +0200
@@ -579,10 +579,6 @@
 extern char *strcasestr(const char *s, const char *pattern) FAST_FUNC;
 #endif
 
-#ifndef HAVE_STRCHRNUL
-extern char *strchrnul(const char *s, int c) FAST_FUNC;
-#endif
-
 #ifndef HAVE_STRSEP
 extern char *strsep(char **stringp, const char *delim) FAST_FUNC;
 #endif