Define NDEBUG for non-debug builds

configure

@@ -3499,6 +3499,10 @@ then
 
 $as_echo "#define DEBUG 1" >>confdefs.h
 
+else
+
+$as_echo "#define NDEBUG 1" >>confdefs.h
+
 fi
 
 ac_ext=c

configure.ac

@@ -40,6 +40,8 @@ then
    CFLAGS="${CFLAGS} -g"
    CXXFLAGS="${CXXFLAGS} -g"
    AC_DEFINE(DEBUG, 1, [Compile with debug code])
+else
+   AC_DEFINE(NDEBUG, 1, [Compile without debug code])
 fi
 
 dnl ###################