issue #146 only affects a single file: wiring_digital.c
Since this file is compiled each time a sketch is built, all that is needed
is an updated version of that file.
Simply check out that single file from the SVN repository.
Or you could simply go get it directly from:http://arduino.googlecode.com/svn/trunk/hardware/arduino/cores/arduino/wiring_digital.c
And then save the file into your installation directory.
(assuming you are using an arduino board)
on 0017: xxx/hardware/cores/arduino
on 0018: xxx/hardware/arduino/cores/arduino
If you are having issues on arduino 0017, keep in mind that 146 also talks about issue 170 (fixed in 0018) which is the delay routine:
delayMicroseconds() in wiring.c that masks interrupts during the delay.