From be387a25bd4a009bbb4c4dda47e353aaa3a5c8e7 Mon Sep 17 00:00:00 2001
From: Marian Buschsieweke <marian.buschsieweke@posteo.net>
Date: Wed, 5 Jun 2024 21:47:56 +0200
Subject: [PATCH] sys/posix: Don't shadow <sys/select.h> on native

This fixes compilation issues on musl, where the host POSIX headers
don't mix well with RIOT's POSIX headers.

This adds an conditional `#include_next <sys/select.h>` to RIOT's
`<sys/select.h>` header.
---
 sys/posix/include/sys/select.h | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/sys/posix/include/sys/select.h b/sys/posix/include/sys/select.h
index 8bf98f7c42..afe63aac15 100644
--- a/sys/posix/include/sys/select.h
+++ b/sys/posix/include/sys/select.h
@@ -29,6 +29,13 @@
 #ifndef SYS_SELECT_H
 #define SYS_SELECT_H
 
+#ifdef CPU_NATIVE
+/* On native, system headers may depend on system's <sys/select.h>. Hence,
+ * include the real sys/select.h here. */
+__extension__
+#include_next <sys/select.h>
+#endif
+
 #include <string.h>
 /* prevent cyclic dependency with newlib/picolibc's `sys/types.h` */
 #if (defined(MODULE_NEWLIB) || defined(MODULE_PICOLIBC)) && !defined(CPU_ESP8266)
@@ -43,6 +50,13 @@
 extern "C" {
 #endif
 
+/**
+ * @brief   @ref core_thread_flags for POSIX select
+ */
+#define POSIX_SELECT_THREAD_FLAG    (1U << 3)
+
+#ifndef CPU_NATIVE
+
 /**
  * @addtogroup  config_posix
  * @{
@@ -59,11 +73,6 @@ extern "C" {
 #endif
 /** @} */
 
-/**
- * @brief   @ref core_thread_flags for POSIX select
- */
-#define POSIX_SELECT_THREAD_FLAG    (1U << 3)
-
 /* ESP's newlib has this already defined in `sys/types.h` */
 #if !defined(CPU_ESP8266)
 /**
@@ -164,6 +173,8 @@ static inline void FD_ZERO(fd_set *fdsetp)
 int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds,
            struct timeval *timeout);
 
+#endif /* CPU_NATIVE */
+
 #ifdef __cplusplus
 }
 #endif