Show message when no Linux file picker is found (#7339)

soh/soh/Extractor/Extract.cpp

@@ -318,6 +318,18 @@ bool Extractor::GetRomPathFromBox() {
     }
     mCurrentRomPath = nameBuffer;
 #else
+    if (!pfd::settings::available()) {
+        std::string msg =
+            "No file picker was found on your system. Ship of Harkinian needs one of these to select a ROM:\n\n"
+            "  - GNOME, Xfce, Cinnamon and other GTK desktops: install \"zenity\"\n"
+            "  - KDE Plasma: install \"kdialog\"\n\n"
+            "On other distributions or window managers, search your package manager.\n\n"
+            "Alternatively, place your ROM in:\n" +
+            mSearchPath + "\nand restart.";
+        ShowErrorBox("File Picker Unavailable", msg.c_str());
+        return false;
+    }
+
     auto selection = pfd::open_file("Select a file", mSearchPath, { "N64 Roms", "*.z64 *.n64 *.v64" }).result();
 
     if (selection.empty()) {