From b651b297513c3dfdaaccab2534ff5ab5efbaacf3 Mon Sep 17 00:00:00 2001
From: Kaspar Schleiser <kaspar@schleiser.de>
Date: Wed, 20 Oct 2021 11:21:57 +0200
Subject: [PATCH] sys/picolibc_syscalls_default: make stdin and stderr strong
 refs

---
 sys/picolibc_syscalls_default/syscalls.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/sys/picolibc_syscalls_default/syscalls.c b/sys/picolibc_syscalls_default/syscalls.c
index a28ec23678..2e4c430852 100644
--- a/sys/picolibc_syscalls_default/syscalls.c
+++ b/sys/picolibc_syscalls_default/syscalls.c
@@ -236,9 +236,18 @@ FILE picolibc_stdio =
     FDEV_SETUP_STREAM(picolibc_put, picolibc_get, picolibc_flush, _FDEV_SETUP_RW);
 
 #ifdef PICOLIBC_STDIO_GLOBALS
-FILE *const stdout = &picolibc_stdio;
+#ifdef __strong_reference
+/* This saves two const pointers.
+ * See https://github.com/RIOT-OS/RIOT/pull/17001#issuecomment-945936918
+ */
+#define STDIO_ALIAS(x) __strong_reference(stdin, x);
+#else
+#define STDIO_ALIAS(x) FILE *const x = &__picolibc_stdio;
+#endif
+
 FILE *const stdin = &picolibc_stdio;
-FILE *const stderr = &picolibc_stdio;
+STDIO_ALIAS(stdout);
+STDIO_ALIAS(stderr);
 #else
 FILE *const __iob[] = {
     &picolibc_stdio,        /* stdin  */