Small improvement on code for building without tdehw.

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>
(cherry picked from commit 0d040704e1)

src/sources/batterysrc.h

@@ -26,7 +26,12 @@
 #include <tqstring.h>
 #include <list>
 
+#ifdef __TDE_HAVE_TDEHWLIB
 class TDEHardwareDevices;
+#else
+#define TDEHardwareDevices void
+#endif
+
 /**
  * BatterySrc fetches the state of charge of the battery from HAL
  * @author Ken Werner