Senselib FFI: Use devDesc object in SenseApiLib, also add per-device metadata to xcbXorg

We also had to write conversion constructors and so on to CSenseDeviceDesc.
The technical debt that's being piled up from this C FFI is excessive.
I think we'll end it here. API Libs will have to be written in C++
from now on. API Lib interfaces will be in C++.

We'll use cross compilers to ensure stability for out-of-tree lib
development.

senseApis/xcbXorg/xcbXorg.cpp

@@ -2,9 +2,24 @@
 #include <algorithm>
 #include <stdexcept>
 #include <memory>
+#include <vector>
 #include <xcb/xcb.h>
 #include "xcbXorg.h"
 
+class AttachedDevice {
+public:
+    AttachedDevice(const CSenseDeviceSpec &spec) : deviceSpec(spec) {}
+
+    const CSenseDeviceSpec& getSpec() const {
+        return deviceSpec;
+    }
+
+private:
+    CSenseDeviceSpec deviceSpec;
+};
+
+static std::vector<AttachedDevice> attachedDevices;
+
 struct XcbConnectionInfo {
     std::unique_ptr<xcb_connection_t, decltype(&xcb_disconnect)> connection;
     int screenNumber;
@@ -82,13 +97,25 @@ int xcbXorg_finalizeInd(void)
 static sal_mlo_attachDeviceReqFn xcbXorg_attachDeviceReq;
 int xcbXorg_attachDeviceReq(const CSenseDeviceSpec *const desc)
 {
-    std::cout << __func__ << ": Attaching device spec: " << *desc << "\n";
+    attachedDevices.emplace_back(*desc);
+
+    std::ostringstream os;
+    for (const auto& device : attachedDevices) {
+        os << device.getSpec();
+    }
+    std::cout << __func__ << ": >>>> Attaching device spec: " << *desc << "\n"
+              << " >>>> Current attached devices:\n" << os.str();
     return 0;
 }
 
 static sal_mlo_detachDeviceReqFn xcbXorg_detachDeviceReq;
 int xcbXorg_detachDeviceReq(const CSenseDeviceSpec *const spec)
 {
-    std::cout << __func__ << "\n";
+    auto it = std::remove_if(attachedDevices.begin(), attachedDevices.end(),
+        [spec](const AttachedDevice &device) {
+            return device.getSpec() == *spec;
+    });
+    attachedDevices.erase(it, attachedDevices.end());
+    std::cout << __func__ << ": Detaching device spec\n";
     return 0;
 }