CMake: Map dlopen feature to 'ON'

Map the dlopen feature to 'ON'. The effect is that cmake will figure
out whether or not linking to 'dl' is necessary or not.

The user-visible feature is 'library' anyway: That enables dynamic
library loading -- and will link in 'dl' as needed.

Change-Id: I0d68275a7234efba7f926150f120bb37b4a1163f
Reviewed-by: Albert Astals Cid <albert.astals.cid@kdab.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

util/cmake/configurejson2cmake.py

@@ -276,7 +276,7 @@ def map_condition(condition):
     assert isinstance(condition, str)
 
     mapped_features = {
-        "dlopen": "UNIX",
+        "dlopen": "ON",
         'gbm': 'gbm_FOUND',
         "system-xcb": "ON",
         "system-freetype": "ON",

util/cmake/pro2cmake.py

@@ -603,6 +603,8 @@ def map_condition(condition: str) -> str:
                 if feature.startswith('system_') and substitute_libs(feature[7:]) != feature[7:]:
                     # Qt6 always uses system libraries!
                     part = 'ON'
+                elif feature == 'dlopen':
+                    part = 'ON'
                 else:
                     part = 'QT_FEATURE_' + feature
         else: