- stack should remain properly aligned
- risc-v was actually completely broken for user defined handlers because GCC was auto-pushing vaargs for naked function even with no stack frame
- new implementation supports full call stacks in gdb for Arm or RISC-V when hitting breakpoint in panic function
- new config defines make it explicit that gdb full stgack trace comes at the cost of corrupting stack based vaargs 4th is corrupted on Arm, later on RiSC-V (7 maybe?)
* * Harden stdio_usb and stdio in general against deadlocks which could otherwise result from doing printfs from within IRQs
* Add a test for the above
* Add mutex_try_enter_block_until API.
* Make best_effort_wfe_or_timeout not use alarms if called from within IRQ
Adds a new cmsis_core INTERFACE library, which provides the basic CMSIS macros/definitions, and RP2040.h and system_RP2040.h
By default the isr_ methods in the vector table are renamed to their CMSIS versions, but this can be overridden by defining PICO_CMSIS_RENAME_EXCEPTIONS=0
