Further improve XLib code and include go code capable of calling it

xdg/xinput_devnodes/main.c

@@ -0,0 +1,16 @@
+#include "devnodes.h"
+#include "xslaves.h"
+
+#include <stdio.h>
+
+
+int main(int argc, char** argv) {
+    XSlaves* xs = get_slave_info();
+    for (int i=0; i < xs->length; i++)
+    {
+        XSlaveInfo si = xs->slaves[i];
+        printf("%s = %s\n", si.name, si.dev_node);
+    }
+
+    free_xslaves(xs);
+}