Separate headers into cpp source files

cpp/include/idevice++/ffi.hpp

@@ -0,0 +1,21 @@
+// Jackson Coxson
+
+#ifndef IDEVICE_FFI
+#define IDEVICE_FFI
+
+#include <idevice++/bindings.hpp>
+#include <string>
+
+namespace IdeviceFFI {
+class FfiError {
+  public:
+    int32_t     code = 0;
+    std::string message;
+
+    FfiError(const IdeviceFfiError* err);
+    FfiError();
+
+    explicit operator bool() const { return code != 0; }
+};
+} // namespace IdeviceFFI
+#endif