CMake: Add "cmake" keyword for test blacklisting

Certain tests fail only on CMake configurations. We need the
capability to ignore these failures, without removing the
qmake-built-Qt coverage for now.

The keyword is enabled when Qt is built with CMake. So it doesn't
matter if the final test is built with CMake or qmake.

Task-number: QTBUG-85364
Change-Id: I157fe3d9254b589ef1e84022c01f4487ff834d27
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

src/testlib/CMakeLists.txt

@@ -133,4 +133,7 @@ qt_add_docs(Test
 
 # special case begin
 qt_apply_testlib_coverage_options(Test)
+
+# Allow blacklisting tests depending on whether testlib was built as part of a CMake build.
+target_compile_definitions(Test PRIVATE QT_CMAKE_BUILD)
 # special case end

src/testlib/qtestblacklist.cpp

@@ -58,7 +58,8 @@ QT_BEGIN_NAMESPACE
   referring to this documentation is kind to readers.  Comments can also be used
   to indicate the reasons for ignoring particular cases.
 
-  The key "ci" applies only when run by COIN.  Other keys name platforms,
+  The key "ci" applies only when run by COIN.
+  The key "cmake" applies when Qt is built using CMake. Other keys name platforms,
   operating systems, distributions, tool-chains or architectures; a !  prefix
   reverses what it checks.  A version, joined to a key (at present, only for
   distributions and for msvc) with a hyphen, limits the key to the specific
@@ -164,6 +165,10 @@ static QSet<QByteArray> keywords()
 #ifdef QT_BUILD_INTERNAL
             << "developer-build"
 #endif
+
+#ifdef QT_CMAKE_BUILD
+            << "cmake"
+#endif
             ;
 
 #if QT_CONFIG(properties)