[Backport] Avoid redefinition warnings, fix export macros

- add missing check

(cherry picked from commit MeVisLab/pythonqt@8f02ebb)

Author: mrbean-bremen

src/PythonQtPythonInclude.h

@@ -33,11 +33,6 @@
 #ifndef __PythonQtPythonInclude_h
 #define __PythonQtPythonInclude_h
 
-// Undefine macros that Python.h defines to avoid redefinition warning.
-#undef _POSIX_C_SOURCE
-#undef _POSIX_THREADS
-#undef _XOPEN_SOURCE
-
 // Undefine Qt keywords that conflict with Python headers
 #ifdef slots
 #undef slots

src/PythonQtSystem.h

@@ -42,15 +42,21 @@
 */
 //----------------------------------------------------------------------------------
 
-#ifdef WIN32
-#ifdef PYTHONQT_EXPORTS
-#define PYTHONQT_EXPORT __declspec(dllexport)
-#else
-#define PYTHONQT_EXPORT __declspec(dllimport)
-#endif
+
+#if defined(WIN32)
+    #ifdef PYTHONQT_EXPORTS
+      #define PYTHONQT_EXPORT __declspec(dllexport)
+    #else
+      #define PYTHONQT_EXPORT __declspec(dllimport)
+    #endif
 #else
-#define PYTHONQT_EXPORT
+    #ifdef PYTHONQT_EXPORTS
+      #define PYTHONQT_EXPORT __attribute__((__visibility__("default")))
+    #else
+      #define PYTHONQT_EXPORT
+    #endif
 #endif
 
+
 #endif
 

src/gui/PythonQtScriptingConsole.cpp

@@ -451,8 +451,9 @@ void PythonQtScriptingConsole::keyPressEvent(QKeyEvent* event) {
   }
 
   if (eventHandled) {
-
-    _completer->popup()->hide();
+    if(_completer != nullptr) {
+        _completer->popup()->hide();
+    }
     event->accept();
 
   } else {