No need for declarations in include file

...of functions only accessed via dlopen

Change-Id: I6b9998298fc6df68fb0d3003cef77a62ecef8976

sfx2/source/appl/shutdownicon.hxx

@@ -170,9 +170,6 @@ extern "C" {
     void aqua_init_systray();
     void aqua_shutdown_systray();
 #  endif
-    // external plugin systray impl.
-    void plugin_init_sys_tray();
-    void plugin_shutdown_sys_tray();
 }
 
 #endif

sfx2/source/appl/shutdowniconunx.cxx

@@ -55,6 +55,13 @@
 
 using namespace ::osl;
 
+extern "C" {
+
+void SAL_DLLPUBLIC_EXPORT plugin_init_sys_tray();
+void SAL_DLLPUBLIC_EXPORT plugin_shutdown_sys_tray();
+
+}
+
 static ResMgr *pVCLResMgr;
 static GtkStatusIcon* pTrayIcon;
 static GtkWidget *pExitMenuItem = NULL;
@@ -360,7 +367,7 @@ static void notify_file_changed(GFileMonitor * /*gfilemonitor*/, GFile * /*arg1*
 }
 #endif
 
-void SAL_DLLPUBLIC_EXPORT plugin_init_sys_tray()
+void plugin_init_sys_tray()
 {
     ::SolarMutexGuard aGuard;
 
@@ -411,7 +418,7 @@ void SAL_DLLPUBLIC_EXPORT plugin_init_sys_tray()
 #endif
 }
 
-void SAL_DLLPUBLIC_EXPORT plugin_shutdown_sys_tray()
+void plugin_shutdown_sys_tray()
 {
     ::SolarMutexGuard aGuard;
     if( !pTrayIcon )