Remove include statements the reference non-existent endian.c which was removed from this toolkit because it was no longer required.
Added conditional include of tools/error.c to support the call to function error on systems that do not have that function. Program mdiogen was intended to compiled stand-alone (ie; without other toolkit modules) but we now have a case (MAC OSX) where it cannot be. This situation will be corrected in the future so that it can be compiled stand-alone.