Add initial support for building for VxWorks using clang

Change-Id: I8c4538cd5582bfea69a6e1890445c4c75e6ca0d7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

mkspecs/common/vxworks/qplatformdefs.h

@@ -0,0 +1,43 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef Q_VXWORKS_PLATFORMDEFS_H
+#define Q_VXWORKS_PLATFORMDEFS_H
+
+#include "qglobal.h"
+
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <sys/time.h>
+#include <dirent.h>
+#include <pthread.h>
+
+// from VxWorks 7 <system.h>
+#ifndef S_ISSOCK
+# ifdef S_IFSOCK
+#   define S_ISSOCK(m) (((m) & S_IFMT) == S_IFSOCK)
+# else
+#   define S_ISSOCK(m) 0
+# endif
+#endif
+
+#include "../common/posix/qplatformdefs.h"
+
+#undef QT_OPEN_LARGEFILE
+
+#define O_LARGEFILE         0
+#define QT_OPEN_LARGEFILE   O_LARGEFILE
+
+#define QT_MMAP                 ::mmap
+
+#define QT_SNPRINTF             ::snprintf
+#define QT_VSNPRINTF            ::vsnprintf
+
+/* vxworks exposes these definitions only when _POSIX_C_SOURCE >=200809L but we don't want to set this, as it hides other API */
+#ifndef UTIME_NOW
+#  define UTIME_NOW       ((1l << 30) - 1l)
+#  define UTIME_OMIT      ((1l << 30) - 2l)
+#endif
+
+#endif /* Q_VXWORKS_PLATFORMDEFS_H */

mkspecs/vxworks-clang/qplatformdefs.h

@@ -0,0 +1,9 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QPLATFORMDEFS_H
+#define QPLATFORMDEFS_H
+
+#include "../common/vxworks/qplatformdefs.h"
+
+#endif // QPLATFORMDEFS_H

src/corelib/global/qsystemdetection.h

@@ -123,7 +123,7 @@
 #  define Q_OS_INTEGRITY
 #elif defined(__rtems__)
 #  define Q_OS_RTEMS
-#elif defined(VXWORKS) /* there is no "real" VxWorks define - this has to be set in the mkspec! */
+#elif defined(__vxworks)
 #  define Q_OS_VXWORKS
 #elif defined(__HAIKU__)
 #  define Q_OS_HAIKU