don't cache test result after pre-dep failure

there is no point in doing that, as we don't load it in that case
anyway. in fact, it would lead to caching a new result in every run.

Change-Id: Ia5cb27fa8a5d705d7f32a785b1e3b944f92d8929
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

mkspecs/features/qt_configure.prf

@@ -870,7 +870,6 @@ defineTest(qtRunSingleTest) {
     tpfx = config.tests.$${1}
     defined($${tpfx}.result, var): \
         return()
-    result = true
 
     type = $$eval($${tpfx}.type)
     call = "qtConfTest_$$type"
@@ -880,25 +879,28 @@ defineTest(qtRunSingleTest) {
     qtConfEnsureTestTypeDeps($$type)
 
     preCall = "qtConfTestPrepare_$$type"
-    defined($$preCall, test): \
-        !$${preCall}($${tpfx}): result = false
-
-    $$result {
-        # note: we do this only after resolving the dependencies and the
-        # preparation (which may resolve libraries), so that caching does
-        # not alter the execution order (and thus the output).
-        qtConfLoadResult($${tpfx}, $$1): \
-            return()
-
-        qtLogTestIntro($${tpfx})
-        msg = "executing config test $${1}"
-        write_file($$QMAKE_CONFIG_LOG, msg, append)
-
-        !$${call}($${tpfx}): result = false
-
-        qtLogTestResult($${tpfx}, $$result)
+    defined($$preCall, test):!$${preCall}($${tpfx}) {
+        $${tpfx}.result = false
+        export($${tpfx}.result)
+        # don't cache the result; the pre-deps have their own caches.
+        return()
     }
 
+    # note: we do this only after resolving the dependencies and the
+    # preparation (which may resolve libraries), so that caching does
+    # not alter the execution order (and thus the output).
+    qtConfLoadResult($${tpfx}, $$1): \
+        return()
+
+    qtLogTestIntro($${tpfx})
+    msg = "executing config test $${1}"
+    write_file($$QMAKE_CONFIG_LOG, msg, append)
+
+    result = false
+    $${call}($${tpfx}): result = true
+
+    qtLogTestResult($${tpfx}, $$result)
+
     $${tpfx}.result = $$result
     export($${tpfx}.result)
     qtConfSaveResult($${tpfx}, $$1)