Do you compile it for ATMEGA8 ? when I compile it for UNO, everything is ok - atmega8 cannot accept software serial so for this reason make error. This is why I found this error. When I use UNO, I can not see when software serial is compiled. it is silent.
My first code i WRONG !!! I compile it with my second code in middle of this topic.
When I use IFDEF, I can hope IDE use include directive.
But I use this :
/*
//------------------------------------------------
//#define DEBUG // zapnout LADENI (zapne software serial) DEBUG 1/2 !!!!
//------------------------------------------------
//#ifdef DEBUG
//#include <SoftwareSerial.h>
//#endif
*/
//SoftwareSerial mySerial(11, 12); // RX, TX
// if DEBUG, MUST be uncomment
and still I GET error about software serial, which IS COMMENTED .....
You must select arduino board : Arduino NG or older w/ Atmega8.... UNO work super with softwareserial and you can not find this error...