build: define KMSCON_ENABLE_DEBUG on --enable-debug

We build several internal libraries and to keep the namespaces apart we
also need different debug constants. Therefore, introduce the new
KMSCON_ENABLE_DEBUG constant which is for every debug object in base
kmscon code.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

configure.ac

@@ -109,6 +109,7 @@ AC_MSG_RESULT([$debug])
 if test ! x$debug = xyes ; then
         AC_DEFINE([NDEBUG], [1], [No Debug])
 else
+        AC_DEFINE([KMSCON_ENABLE_DEBUG], [1], [Enable debug for kmscon])
         AC_DEFINE([LOG_ENABLE_DEBUG], [1], [Enable debug for log subsystem])
 fi