Upgrade AVR-GCC to GCC-3.4.4.
By the same time, combine all the patches that add support for new AVR
devices into a single patch, as they all touch the same three source
files. In total, add support for the following AVR devices that were
not supported by the stock GCC 3.4.x:
ATtiny13/ATtiny2313
ATtiny25/ATtiny45/ATtiny85
ATmega48/ATmega88/ATmega168
AT90PWM2/AT90PWM3
ATmega164/ATmega324/ATmega644
ATmega325/ATmega3250/ATmega645/ATmega6450
ATmega329/ATmega3290/ATmega649/ATmega6490
AT90CAN128
(This is now documented in pkg-descr as well.)
Bring in some patches from the head of GCC's CVS back to the latest
released version, 3.4.3. This mainly adds support for new AVR devices
that appeared on the market recently, and fixes a bug related to the
order of assignments for volatile uint16_t * objects (in the
assumption they might point to IO space where the order of two 8-bit
operations can be important).
