Execution abstraction and build fix for linux and mac

xs/src/libslic3r/PrintExport.hpp

@@ -175,7 +175,7 @@ public:
 
         wxFFileOutputStream zipfile(path);
 
-        std::string project = filepath.GetName();
+        std::string project = filepath.GetName().ToStdString();
 
         if(!zipfile.IsOk()) {
             BOOST_LOG_TRIVIAL(error) << "Can't create zip file for layers! "

xs/src/slic3r/AppController.cpp

@@ -318,7 +318,9 @@ void PrintController::slice_to_png()
         report_issue(IssueType::WARN, ss.str(), "Warning");
     }
 
-    std::async(std::launch::async, [this, exd]() {
+    std::async(supports_asynch()? std::launch::async : std::launch::deferred,
+               [this, exd]()
+    {
         progress_indicator(100, "Slicing to zipped png files...");
         progress_indicator()->procedure_count(3);
 

xs/src/slic3r/AppController.hpp

@@ -131,6 +131,22 @@ public:
      */
     bool is_main_thread() const;
 
+    /**
+     * @brief The frontend supports asynch execution.
+     *
+     * A Graphic UI will support this, a CLI may not. This can be used in
+     * subclass methods to decide whether to start threads for block free UI.
+     *
+     * Note that even a progress indicator's update called regularly can solve
+     * the blocking UI problem in some cases even when an event loop is present.
+     * This is how wxWidgets gauge work but creating a separate thread will make
+     * the UI even more fluent.
+     *
+     * @return true if a job or method can be executed asynchronously, false
+     * otherwise.
+     */
+    bool supports_asynch() const;
+
 protected:
 
     /**

xs/src/slic3r/AppControllerWx.cpp

@@ -1,6 +1,7 @@
 #include "AppController.hpp"
 
 #include <thread>
+#include <future>
 
 #include <slic3r/GUI/GUI.hpp>
 #include <slic3r/GUI/PngExportDialog.hpp>
@@ -20,6 +21,11 @@
 
 namespace Slic3r {
 
+bool AppControllerBoilerplate::supports_asynch() const
+{
+    return true;
+}
+
 AppControllerBoilerplate::PathList
 AppControllerBoilerplate::query_destination_paths(
         const std::string &title,