Build: Add XCB_LIBS; Skeleton: mlo_initializeInd, mlo_attachDeviceReq

* Renamed some of the Sense API lib classes
  (CSensorDeviceDesc=>CSenseDeviceDesc,
  SensorDeviceDesc=>SenseDeviceDesc).
* Moved SenseApiDesc into /include/user/senseApiDesc.
* Add conversion constructor to convert from SenseDeviceDesc
  to
* Wireframe mlo_initializeInd to call xcb_connect().
* Add $(XCB_LIBS) to libxcbXorg_LDFLAGS.
* Wireframe mlo_attachDeviceReq().

senseApis/xcbXorg/xcbXorg.cpp

@@ -1,8 +1,19 @@
 #include <iostream>
 #include <algorithm>
 #include <stdexcept>
+#include <memory>
+#include <xcb/xcb.h>
 #include "xcbXorg.h"
 
+struct XcbConnectionInfo {
+    std::unique_ptr<xcb_connection_t, decltype(&xcb_disconnect)> connection;
+    int screenNumber;
+
+    XcbConnectionInfo()
+        : connection(nullptr, &xcb_disconnect), screenNumber(0) {}
+};
+
+static XcbConnectionInfo xcbConn;
 
 static CExportedImplexorApiDesc xcbXorgExportedImplexorApis[] =
 {
@@ -43,27 +54,41 @@ const CSenseApiDesc *HK_GET_SENSE_API_DESC_FN_NAME(void)
 static sal_mlo_initializeIndFn xcbXorg_initializeInd;
 int xcbXorg_initializeInd(void)
 {
-    std::cerr << "XcbXorg::sal_mlo_initializeInd\n";
+    xcbConn.connection.reset(
+        xcb_connect(nullptr, &xcbConn.screenNumber));
+
+    if (xcb_connection_has_error(xcbConn.connection.get()))
+    {
+        throw std::runtime_error(
+            std::string(__func__) + ": Failed to connect to X server");
+    }
+
+    std::cout << __func__ << ": Connected to X server, screen number "
+              << xcbConn.screenNumber << "\n";
     return 0;
 }
 
 static sal_mlo_finalizeIndFn xcbXorg_finalizeInd;
 int xcbXorg_finalizeInd(void)
 {
-    std::cerr << "XcbXorg::sal_mlo_finalizeInd\n";
+    if (!xcbConn.connection) {
+        return 0;
+    }
+    xcbConn.connection.reset();
+    std::cout << __func__ << ": Disconnected from X server\n";
     return 0;
 }
 
 static sal_mlo_attachDeviceReqFn xcbXorg_attachDeviceReq;
-int xcbXorg_attachDeviceReq(void)
+int xcbXorg_attachDeviceReq(const CSenseDeviceSpec *const desc)
 {
-    std::cerr << "XcbXorg::sal_mlo_attachDeviceReq\n";
+    std::cout << __func__ << "\n";
     return 0;
 }
 
 static sal_mlo_detachDeviceReqFn xcbXorg_detachDeviceReq;
-int xcbXorg_detachDeviceReq(void)
+int xcbXorg_detachDeviceReq(const CSenseDeviceSpec *const spec)
 {
-    std::cerr << "XcbXorg::sal_mlo_detachDeviceReq\n";
+    std::cout << __func__ << "\n";
     return 0;
 }