don't cache results of build_parts and skip_modules

as these tests do nothing but validating the command line, caching the
result is more confusing than anything else.

also make the tests silent, so they don't clutter an otherwise fully
cached configure run.

Change-Id: Ifc3d65278769b36a056650f077fd6274a7e192e7
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

configure.json

@@ -858,14 +858,10 @@
             "test": "unix/reduce_relocs"
         },
         "skip_modules": {
-            "description": "modules to skip",
-            "type": "skipModules",
-            "log": "value"
+            "type": "skipModules"
         },
         "build_parts": {
-            "description": "parts of Qt to build",
-            "type": "buildParts",
-            "log": "value"
+            "type": "buildParts"
         },
         "dlopen": {
             "description": "dlopen() in libc",
@@ -2104,7 +2100,6 @@
             "output": [ { "type": "varAssign", "name": "QT_SKIP_MODULES", "value": "tests.skip_modules.value" } ]
         },
         "build_parts": {
-            "description": "Qt build parts",
             "output": [ { "type": "varAppend", "name": "QT_BUILD_PARTS", "value": "tests.build_parts.value" } ]
         },
         "qreal": {

configure.pri

@@ -203,6 +203,9 @@ defineTest(qtConfTest_neon) {
 }
 
 defineTest(qtConfTest_skipModules) {
+    $${1}.cache = -
+    export($${1}.cache)
+
     skip =
     uikit {
         skip += qtdoc qtmacextras qtserialport qtwebkit qtwebkit-examples
@@ -220,8 +223,6 @@ defineTest(qtConfTest_skipModules) {
     }
     $${1}.value = $$unique(skip)
     export($${1}.value)
-    $${1}.cache += value
-    export($${1}.cache)
     return(true)
 }
 
@@ -243,7 +244,7 @@ defineTest(qtConfTest_buildParts) {
 
     $${1}.value = $$parts
     export($${1}.value)
-    $${1}.cache += value
+    $${1}.cache = -
     export($${1}.cache)
     return(true)
 }

mkspecs/features/qt_configure.prf

@@ -789,6 +789,8 @@ defineTest(qtLogTestResult) {
 }
 
 defineTest(qtConfSaveResult) {
+    equals($${1}.cache, -): \
+        return()
     keys = result $$eval($${1}.cache)
     cont = "cache.$${2}._KEYS_ = $$keys"
     for (k, keys): \