Handle VxWorks in QFileSelector

QFileSelector tests fail, because VxWorks is not properly categorized.
Even though it is not a unix-like system, it does provide a
compatibility layer that enables some unix utilities.
It has also been treated as unix on the Qt 5 customer branch.

Solve the issue by assigning VxWorks to the unix category in
QFileSelector and its tests

Task-number: QTBUG-115777
Pick-to: 6.7 6.8
Change-Id: Icab80764b66b121995f51ddf149de55dc8c9eb55
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qfileselector.cpp

@@ -318,8 +318,9 @@ QStringList QFileSelectorPrivate::platformSelectors()
     ret << QSysInfo::kernelType();  // "winnt"
 #elif defined(Q_OS_UNIX)
     ret << QStringLiteral("unix");
-#  if !defined(Q_OS_ANDROID) && !defined(Q_OS_QNX)
+#  if !defined(Q_OS_ANDROID) && !defined(Q_OS_QNX) && !defined(Q_OS_VXWORKS)
     // we don't want "linux" for Android or two instances of "qnx" for QNX
+    // or two instances of "vxworks" for vxworks
     ret << QSysInfo::kernelType();
 #  endif
     QString productName = QSysInfo::productType();

tests/auto/corelib/io/qfileselector/CMakeLists.txt

@@ -47,8 +47,11 @@ set(qfileselector_resource_files
     "platforms/+unix/+haiku/test"
     "platforms/+unix/+linux/test"
     "platforms/+unix/+qnx/test"
+    "platforms/+unix/+vxworks/test"
     "platforms/+unix/test"
     "platforms/+unix/test3"
+    "platforms/+vxworks/test"
+    "platforms/+vxworks/test2"
     "platforms/+wince/test"
     "platforms/+wince/test2"
     "platforms/+windows/+wince/test"

tests/auto/corelib/io/qfileselector/tst_qfileselector.cpp

@@ -61,7 +61,7 @@ void tst_QFileSelector::basicTest_data()
     QString expectedPlatform2File(""); //Only the last selector
     QString expectedPlatform3File; // Only the first selector (the family)
 #if defined(Q_OS_UNIX) && !defined(Q_OS_ANDROID) && !defined(Q_OS_WASM) && \
-    !defined(Q_OS_DARWIN) && !defined(Q_OS_LINUX) && !defined(Q_OS_HAIKU) && !defined(Q_OS_QNX)
+    !defined(Q_OS_DARWIN) && !defined(Q_OS_LINUX) && !defined(Q_OS_HAIKU) && !defined(Q_OS_QNX) && !defined(Q_OS_VXWORKS)
     /* We are only aware of specific unixes, and do not have test files for any of the others.
        However those unixes can get a selector added from the result of a uname call, so this will
        lead to a case where we don't have that file so we can't expect the concatenation of platform