Let's see what this breaks...

src/input/kbMatrixImpl.cpp

@@ -0,0 +1,16 @@
+#include "kbMatrixImpl.h"
+#include "InputBroker.h"
+
+KbMatrixImpl *kbMatrixImpl;
+
+KbMatrixImpl::KbMatrixImpl() : KbMatrixBase("matrixKB") {}
+
+void KbMatrixImpl::init()
+{
+    if (!INPUTBROKER_MATRIX_TYPE) {
+        disable();
+        return;
+    }
+
+    inputBroker->registerSource(this);
+}