Success!
Or at least not total failure
(I changed so many parameters, I'm not quite sure what made a difference 
)
Now it will compile, but still not fall asleep.
(This starts to remind me, of when the kids were small!)
I uninstalled the core, and reinstalled the one Erni linked to.
Then I transplanted major parts of the code from here:
(I tested it on a tiny with an LED. It goes to 5 microamps when sleeping!)
http://www.insidegadgets.com/2011/02/05/reduce-attiny-power-consumption-by-sleeping-with-the-watchdog-timer/
/*
* Watchdog Sleep Example
* Demonstrate the Watchdog and Sleep Functions
* LED on digital pin 0
*
* KHM 2008 / Lab3/ Martin Nawrath nawrath@khm.de
* Kunsthochschule fuer Medien Koeln
* Academy of Media Arts Cologne
*
* Modified on 5 Feb 2011 by InsideGadgets (www.insidegadgets.com)
* to suit the ATtiny85 and removed the cbi( MCUCR,SE ) section
* in setup() to match the Atmel datasheet recommendations
*/
#include <avr/sleep.h>
#include <avr/wdt.h>
#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif
int pinLed = 0;
volatile boolean f_wdt = 1;
void setup(){
pinMode(pinLed,OUTPUT);
setup_watchdog(8); // approximately 4 seconds sleep
}
void loop(){
if (f_wdt==1) { // wait for timed out watchdog / flag is set when a watchdog timeout occurs
f_wdt=0; // reset flag
digitalWrite(pinLed,HIGH); // let led blink
delay(1000);
digitalWrite(pinLed,LOW);
pinMode(pinLed,INPUT); // set all used port to intput to save power
system_sleep();
pinMode(pinLed,OUTPUT); // set all ports into state before sleep
}
}
// set system into the sleep state
// system wakes up when wtchdog is timed out
void system_sleep() {
cbi(ADCSRA,ADEN); // switch Analog to Digitalconverter OFF
set_sleep_mode(SLEEP_MODE_PWR_DOWN); // sleep mode is set here
sleep_enable();
sleep_mode(); // System sleeps here
sleep_disable(); // System continues execution here when watchdog timed out
sbi(ADCSRA,ADEN); // switch Analog to Digitalconverter ON
}
// 0=16ms, 1=32ms,2=64ms,3=128ms,4=250ms,5=500ms
// 6=1 sec,7=2 sec, 8=4 sec, 9= 8sec
void setup_watchdog(int ii) {
byte bb;
int ww;
if (ii > 9 ) ii=9;
bb=ii & 7;
if (ii > 7) bb|= (1<<5);
bb|= (1<<WDCE);
ww=bb;
MCUSR &= ~(1<<WDRF);
// start timed sequence
WDTCR |= (1<<WDCE) | (1<<WDE);
// set new watchdog timeout value
WDTCR = bb;
WDTCR |= _BV(WDIE);
}
// Watchdog Interrupt Service / is executed when watchdog timed out
ISR(WDT_vect) {
f_wdt=1; // set global flag
}
And it ended up looking like this:
Compiling, but not going to sleep like a good little Tiny should!
/*
Cable storage locker alarm
ATTINY VERSION 5
With power saving according to http://www.insidegadgets.com/2011/02/05/reduce-attiny-power-consumption-by-sleeping-with-the-watchdog-timer/
Code transplanted shamelessly from the "ATtiny85_watchdog_example"
Callibration is based on
http://arduino.cc/en/Tutorial/Calibration
David A Mellis and Tom Igoe
By Peter_I 2014
The circuit:
* LDR attached to analog input 1 and 5V with 10k pull down to GND
* Siren attached digital pin 0
* Piezo beeper attached to pin 1 (PWM)
(If used on Arduino, adjust pins accordingly)
Only sensorMax is interesting, and an "intrusion" is considered to be when
"sensorMax + treshold" is exceeded.
"Intrusion" results in short beeps, 2 sec delay followed by the siren.
The short beeps will remind me to switch off the alarm when I open the locker.
*/
#include <avr/sleep.h>
#include <avr/wdt.h>
#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif
//The constants:
const int sensorPin = A1; // pin that the sensor is attached to
const int sirenPin = 0; // pin that the LED is attached to, 0 on ATTiny
const int beepPin = 1; // piezobeeper on PWM pin
const int treshold = 100; // treshold value
const int beepLength = 1000; // A long beep, max 1500ms
const int shortBeep = 100; // and a shorter beep
const int sirenTime = 30000; // How long to wail
// variables:
int sensorValue = 0; // the sensor value
int sensorMax = 0; // maximum sensor value
long previousMillis = 0; // for timing
unsigned long currentMillis = 0; // for timing
volatile boolean f_wdt = 1;
void setup()
{
setup_watchdog(8); // approximately 4 seconds sleep
// 0=16ms, 1=32ms,2=64ms,3=128ms,4=250ms,5=500ms
// 6=1 sec,7=2 sec, 8=4 sec, 9= 8sec
// Serial.begin(9600); // comm, disable on ATTiny
// turn on LED to signal the start of the calibration period:
pinMode(sirenPin, OUTPUT);
pinMode (beepPin, OUTPUT);
analogWrite(beepPin, 128); //3 beeps to give time to close door
delay (beepLength);
analogWrite(beepPin, 0);
delay (beepLength);
analogWrite(beepPin, 128);
delay (beepLength);
analogWrite(beepPin, 0);
delay (beepLength);
analogWrite(beepPin, 128);
delay (beepLength);
analogWrite(beepPin, 0);
// calibrate during the next five seconds
while (millis() < 10000)
{
sensorValue = analogRead(sensorPin);
// record the maximum sensor value
if (sensorValue > sensorMax)
{
sensorMax = sensorValue;
// Serial.print("sensorMax= ");
// Serial.println(sensorMax);
}
}
// signal the end of the calibration period
analogWrite(beepPin, 128); //Long beep to signal "ARMED"
delay (2*beepLength);
analogWrite(beepPin, 0);
}
void loop()
{
if (f_wdt==1) // wait for timed out watchdog / flag is set when a watchdog timeout occurs
{
f_wdt=0; // reset flag
sensorValue = analogRead(sensorPin); // read the sensor
if (sensorValue > treshold + sensorMax) //is there light from an open door?
{
// Serial.println(sensorValue);
//3 quick beeps to signal "Alarm tripped!"
analogWrite(beepPin, 128);
delay (shortBeep);
analogWrite(beepPin, 0);
delay (2*shortBeep);
analogWrite(beepPin, 128);
delay (shortBeep);
analogWrite(beepPin, 0);
delay (2*shortBeep);
analogWrite(beepPin, 128);
delay (shortBeep);
analogWrite(beepPin, 0);
delay (2*shortBeep);
// end of beepery. Now, you have 2 more seconds to switch off, or I'll scream
delay (2000); // said 2 seconds
digitalWrite (sirenPin, HIGH); // You didn't make it: Wheeeeeeeeeeeeeeeeeeeeeeeeeee!
delay (sirenTime);
} // end of "is there an intruder?" if loop
else
digitalWrite (sirenPin, LOW); // off
delay (1);
} // end of watchdog loop
} //end of void loop
// set system into the sleep state
// system wakes up when wtchdog is timed out
void system_sleep() {
cbi(ADCSRA,ADEN); // switch Analog to Digitalconverter OFF
set_sleep_mode(SLEEP_MODE_PWR_DOWN); // sleep mode is set here
sleep_enable();
sleep_mode(); // System sleeps here
sleep_disable(); // System continues execution here when watchdog timed out
sbi(ADCSRA,ADEN); // switch Analog to Digitalconverter ON
}
// 0=16ms, 1=32ms,2=64ms,3=128ms,4=250ms,5=500ms
// 6=1 sec,7=2 sec, 8=4 sec, 9= 8sec
void setup_watchdog(int ii) {
byte bb;
int ww;
if (ii > 9 ) ii=9;
bb=ii & 7;
if (ii > 7) bb|= (1<<5);
bb|= (1<<WDCE);
ww=bb;
MCUSR &= ~(1<<WDRF);
// start timed sequence
WDTCR |= (1<<WDCE) | (1<<WDE);
// set new watchdog timeout value
WDTCR = bb;
WDTCR |= _BV(WDIE);
}
// Watchdog Interrupt Service / is executed when watchdog timed out
ISR(WDT_vect) {
f_wdt=1; // set global flag
}