libc/picolibc: Add 'write' implementation when needed

This is needed for the picolibc __chk_fail implementation as that
uses it up through version 1.8.5. After that, picolibc uses puts.

Signed-off-by: Keith Packard <[email protected]>

lib/libc/picolibc/CMakeLists.txt

@@ -9,6 +9,7 @@ zephyr_library_sources(
   exit.c
   locks.c
   stdio.c
+  write.c
   )
 
 # define __LINUX_ERRNO_EXTENSIONS__ so we get errno defines like -ESHUTDOWN

lib/libc/picolibc/write.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright © 2021, Keith Packard <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <zephyr/posix/sys/stat.h>
+#include <sys/time.h>
+#include <zephyr/arch/cpu.h>
+#include <zephyr/linker/linker-defs.h>
+#include <zephyr/sys/util.h>
+#include <zephyr/sys/errno_private.h>
+#include <zephyr/sys/libc-hooks.h>
+#include <zephyr/internal/syscall_handler.h>
+#include <zephyr/app_memory/app_memdomain.h>
+#include <zephyr/init.h>
+#include <zephyr/sys/sem.h>
+#include <zephyr/logging/log.h>
+#ifdef CONFIG_MMU
+#include <zephyr/sys/mem_manage.h>
+#endif
+
+/* Don't replace the version supplied by fdtable */
+#if !defined(CONFIG_FDTABLE) || !defined(CONFIG_POSIX_API)
+ssize_t write(int fd, const void *buf, size_t len)
+{
+	size_t count;
+	const char *b = buf;
+
+	(void) fd;
+	for (count = 0; count < len; count++)
+		zephyr_fputc(*b++, stdout);
+	return len;
+}
+#endif