Check in strchrnul.c file missing in previous checkin

newlib/libc/string/strchrnul.c

@@ -0,0 +1,49 @@
+/*
+FUNCTION
+	<<strchrnul>>---search for character in string
+
+INDEX
+	strchrnul
+
+ANSI_SYNOPSIS
+	#include <string.h>
+	char * strchrnul(const char *<[string]>, int <[c]>);
+
+TRAD_SYNOPSIS
+	#include <string.h>
+	char * strchrnul(<[string]>, <[c]>);
+	const char *<[string]>;
+	int <[c]>;
+
+DESCRIPTION
+	This function finds the first occurence of <[c]> (converted to
+	a char) in the string pointed to by <[string]> (including the
+	terminating null character).
+
+RETURNS
+	Returns a pointer to the located character, or a pointer
+	to the concluding null byte if <[c]> does not occur in <[string]>.
+
+PORTABILITY
+<<strchrnul>> is a GNU extension.
+
+<<strchrnul>> requires no supporting OS subroutines.  It uses
+strchr() and strlen() from elsewhere in this library.
+
+QUICKREF
+	strchrnul
+*/
+
+#include <string.h>
+
+char *
+_DEFUN (strchrnul, (s1, i),
+	_CONST char *s1 _AND
+	int i)
+{
+  char *s = strchr(s1, i);
+
+  if (*s != NULL)
+    return s;
+  return (char *)s1 + strlen(s1);
+}