update cmake: Simplify PythonQt_QtAll reusing PYTHONQT_EXPORT export macro

Author: jamesobutler

extensions/PythonQt_QtAll/PythonQt_QtAll.cpp

@@ -76,7 +76,7 @@ void PythonQt_init_QtWebKit(PyObject*);
 #endif
 
 namespace PythonQt_QtAll {
-PYTHONQT_EXPORT void init()
+PYTHONQT_QTALL_EXPORT void init()
 {
 #ifdef PYTHONQT_WITH_CORE
   PythonQt_init_QtCore(0);

extensions/PythonQt_QtAll/PythonQt_QtAll.h

@@ -33,11 +33,28 @@
  *
  */
 
-#include "PythonQtSystem.h" // For PYTHONQT_EXPORT
+// 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
+  #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 bindings enabled at configuration time
-PYTHONQT_EXPORT void init();
+PYTHONQT_QTALL_EXPORT void init();
 }
 
 #endif