cmake/tests: fix PythonQt_QtAll exports and QtCore wrap handling

make PythonQt_QtAll export macro treat both PYTHONQT_QTALL_EXPORTS and PYTHONQT_EXPORTS as build context

Co-authored-by: James Butler <james.butler@revvity.com>

Author: jcfr

extensions/PythonQt_QtAll/PythonQt_QtAll.h

@@ -33,18 +33,27 @@
  *
  */
 
-#ifdef WIN32
-  #ifdef PYTHONQT_QTALL_EXPORTS
+// Export macro for the PythonQt_QtAll symbols.
+// qmake builds define PYTHONQT_QTALL_EXPORTS for the dedicated QtAll DLL,
+// while CMake builds compile this source into the PythonQt target which defines
+// PYTHONQT_EXPORTS. Treat either define as "building" to avoid dllimport on
+// in-target function definitions.
+#if defined(WIN32)
+  #if defined(PYTHONQT_QTALL_EXPORTS) || defined(PYTHONQT_EXPORTS)
     #define PYTHONQT_QTALL_EXPORT __declspec(dllexport)
   #else
     #define PYTHONQT_QTALL_EXPORT __declspec(dllimport)
   #endif
 #else
-  #define PYTHONQT_QTALL_EXPORT
+  #if defined(PYTHONQT_QTALL_EXPORTS) || defined(PYTHONQT_EXPORTS)
+    #define PYTHONQT_QTALL_EXPORT __attribute__((__visibility__("default")))
+  #else
+    #define PYTHONQT_QTALL_EXPORT
+  #endif
 #endif
 
 namespace PythonQt_QtAll {
-//! initialize the Qt binding
+//! Initialize the Qt bindings enabled at configuration time
 PYTHONQT_QTALL_EXPORT void init();
 }