lib: libc: arcmwdt: replace the fileno macro

The fileno macro defined in ARC MWDT headers conflicts with the fileno()
function defined in lib/posix/options/device_io.c. We should undefine it
and replace with a POSIX-compliant declaration and a weak definition.

Signed-off-by: Ilya Tagunov <Ilya.Tagunov@synopsys.com>

lib/libc/arcmwdt/include/stdio.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2024 Synopsys
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef LIB_LIBC_ARCMWDT_INCLUDE_STDIO_H_
+#define LIB_LIBC_ARCMWDT_INCLUDE_STDIO_H_
+
+#include_next <stdio.h>
+
+#ifdef fileno
+#undef fileno
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern int fileno(FILE *file);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LIB_LIBC_ARCMWDT_INCLUDE_STDIO_H_ */

lib/libc/arcmwdt/libc-hooks.c

@@ -71,6 +71,13 @@ int _write(int fd, const char *buf, unsigned int nbytes)
 }
 #endif
 
+#ifndef CONFIG_POSIX_DEVICE_IO
+__weak int fileno(FILE *file)
+{
+	return _fileno(file);
+}
+#endif
+
 /*
  * It's require to implement _isatty to have STDIN/STDOUT/STDERR buffered
  * properly.