0.14.1
---
* **command-line**
  - support for Go 1.15
* **compiler**
  - loader:  work around Windows symlink limitation

0.14.0
---
* **command-line**
  - fix `getDefaultPort()` on non-English Windows locales
  - compileopts: improve error reporting of unsupported flags
  - fix test subcommand
  - use auto-retry to locate MSD for UF2 and HEX flashing
  - fix touchSerialPortAt1200bps on Windows
  - support package names with backslashes on Windows
* **compiler**
  - fix a few crashes due to named types
  - add support for atomic operations
  - move the channel blocked list onto the stack
  - fix -gc=none
  - fix named string to `[]byte` slice conversion
  - implement func value and builtin defers
  - add proper parameter names to runtime.initAll, to fix a panic
  - builder: fix picolibc include path
  - builder: use newer version of gohex
  - builder: try to determine stack size information at compile time
  - builder: remove -opt=0
  - interp: fix sync/atomic.Value load/store methods
  - loader: add Go module support
  - transform: fix debug information in func lowering pass
  - transform: do not special-case zero or one implementations of a method call
  - transform: introduce check for method calls on nil interfaces
  - transform: gc: track 0-index GEPs to fix miscompilation
* **cgo**
  - Add LDFlags support
* **standard library**
  - extend stdlib to allow import of more packages
  - replace master/slave terminology with appropriate alternatives (MOSI->SDO
    etc)
  - `internal/bytealg`: reimplement bytealg in pure Go
  - `internal/task`: fix nil panic in (*internal/task.Stack).Pop
  - `os`: add Args and stub it with mock data
  - `os`: implement virtual filesystem support
  - `reflect`: add Cap and Len support for map and chan
  - `runtime`: fix return address in scheduler on RISC-V
  - `runtime`: avoid recursion in printuint64 function
  - `runtime`: replace ReadRegister with AsmFull inline assembly
  - `runtime`: fix compilation errors when using gc.extalloc
  - `runtime`: add cap and len support for chans
  - `runtime`: refactor time handling (improving accuracy)
  - `runtime`: make channels work in interrupts
  - `runtime/interrupt`: add cross-chip disable/restore interrupt support
  - `sync`: implement `sync.Cond`
  - `sync`: add WaitGroup
* **targets**
  - `arm`: allow nesting in DisableInterrupts and EnableInterrupts
  - `arm`: make FPU configuraton consistent
  - `arm`: do not mask fault handlers in critical sections
  - `atmega2560`: fix pin mapping for pins D2, D5 and the L port
  - `atsamd`: return an error when an incorrect PWM pin is used
  - `atsamd`: add support for pin change interrupts
  - `atsamd`: add DAC support
  - `atsamd21`: add more ADC pins
  - `atsamd51`: fix ROM / RAM size on atsamd51j20
  - `atsamd51`: add more pins
  - `atsamd51`: add more ADC pins
  - `atsamd51`: add pin change interrupt settings
  - `atsamd51`: extend pinPadMapping
  - `arduino-nano33`: use (U)SB flag to ensure that device can be found when
     not on default port
  - `arduino-nano33`: remove (d)ebug flag to reduce console noise when flashing
  - `avr`: use standard pin numbering
  - `avr`: unify GPIO pin/port code
  - `avr`: add support for PinInputPullup
  - `avr`: work around codegen bug in LLVM 10
  - `avr`: fix target triple
  - `fe310`: remove extra println left in by mistake
  - `feather-nrf52840`: add support for the Feather nRF52840
  - `maixbit`: add board definition and dummy runtime
  - `nintendoswitch`: Add experimental Nintendo Switch support without CRT
  - `nrf`: expose the RAM base address
  - `nrf`: add support for pin change interrupts
  - `nrf`: add microbit-s110v8 target
  - `nrf`: fix bug in SPI.Tx
  - `nrf`: support debugging the PCA10056
  - `pygamer`: add Adafruit PyGamer suport
  - `riscv`: fix interrupt configuration bug
  - `riscv`: disable linker relaxations during gp init
  - `stm32f4disco`: add new target with ST-Link v2.1 debugger
  - `teensy36`: add Teensy 3.6 support
  - `wasm`: fix event handling
  - `wasm`: add --no-demangle linker option
  - `wioterminal`: add support for the Seeed Wio Terminal
  - `xiao`: add support for the Seeed XIAO

0.13.1
---
* **standard library**
  - `runtime`: do not put scheduler and GC code in the same section
  - `runtime`: copy stack scan assembly for GBA
* **boards**
  - `gameboy-advance`: always use ARM mode instead of Thumb mode


0.13.0
---
* **command line**
  - use `gdb-multiarch` for debugging Cortex-M chips
  - support `tinygo run` with simavr
  - support LLVM 10
  - support Go 1.14
  - retry 3 times when attempting to do a 1200-baud reset
* **compiler**
  - mark the `abort` function as noreturn
  - fix deferred calls to exported functions
  - add debug info for local variables
  - check for channel size limit
  - refactor coroutine lowering
  - add `dereferenceable_or_null` attribute to pointer parameters
  - do not perform nil checking when indexing slices and on `unsafe.Pointer`
  - remove `runtime.isnil` hack
  - use LLVM builtins for runtime `memcpy`/`memmove`/`memzero` functions
  - implement spec-compliant shifts on negative/overflow
  - support anonymous type asserts
  - track pointer result of string concatenation for GC
  - track PHI nodes for GC
  - add debug info to goroutine start wrappers
  - optimize comparing interface values against nil
  - fix miscompilation when deferring an interface call
  - builder: include picolibc for most baremetal targets
  - builder: run tools (clang, lld) as separate processes
  - builder: use `-fshort-enums` consistently
  - interp: add support for constant type asserts
  - interp: better support for interface operations
  - interp: include backtrace with error
  - transform: do not track const globals for GC
  - transform: replace panics with source locations
  - transform: fix error in interface lowering pass
  - transform: make coroutine lowering deterministic
  - transform: fix miscompilation in func lowering
* **cgo**
  - make `-I` and `-L` paths absolute
* **standard library**
  - `machine`: set the USB VID and PID to the manufacturer values
  - `machine`: correct USB CDC composite descriptors
  - `machine`: move `errors.New` calls to globals
  - `runtime`: support operations on nil maps
  - `runtime`: fix copy builtin return value on AVR
  - `runtime`: refactor goroutines
  - `runtime`: support `-scheduler=none` on most platforms
  - `runtime`: run package initialization in the main goroutine
  - `runtime`: export `malloc` / `free` for use from C
  - `runtime`: add garbage collector that uses an external allocator
  - `runtime`: scan callee-saved registers while marking the stack
  - `runtime`: remove recursion from conservative GC
  - `runtime`: fix blocking select on nil channel
  - `runtime/volatile`: include `ReplaceBits` method
  - `sync`: implement trivial `sync.Map`
* **targets**
  - `arm`: use `-fomit-frame-pointer`
  - `atmega1284`: support this chip for testing purposes
  - `atsamd51`: make QSPI available on all boards
  - `atsamd51`: add support for ADC1
  - `atsamd51`: use new interrupt registration in UART code
  - `attiny`: clean up pin definitions
  - `avr`: use the correct RAM start address
  - `avr`: pass the correct `-mmcu` flag to the linker
  - `avr`: add support for tasks scheduler (disabled by default)
  - `avr`: fix linker problem with overlapping program/data areas
  - `nrf`: fix typo in pin configuration options
  - `nrf`: add lib/nrfx/mdk to include dirs
  - `nrf52840`: implement USB-CDC
  - `riscv`: implement VirtIO target and add RISC-V integration test
  - `riscv`: add I2C support for the HiFive1 rev B board
  - `stm32`: refactor GPIO pin handling
  - `stm32`: refactor UART code
  - `stm32f4`: add SPI
  - `wasm`: support Go 1.14 (breaking previous versions)
  - `wasm`: support `syscall/js.CopyBytesToJS`
  - `wasm`: sync polyfills from Go 1.14.
* **boards**
  - `arduino-mega2560`: add the Arduino Mega 2560
  - `clue-alpha`: add the Adafruit CLUE Alpha
  - `gameboy-advance`: enable debugging with GDB
  - `particle-argon`: add the Particle Argon board
  - `particle-boron`: add the Particle Boron board
  - `particle-xenon`: add the Particle Xenon board
  - `reelboard`: add `reelboard-s140v7` SoftDevice target

0.12.0
---
* **command line**
  - add initial FreeBSD support
  - remove getting a serial port in gdb subcommand
  - add support for debugging through JLinkGDBServer
  - fix CGo when cross compiling
  - remove default port check for Digispark as micronucleus communicates directly using HID
  - differentiate between various serial/USB error messages
* **builder**
  - improve detection of Clang headers
* **compiler**
  - fix assertion on empty interface
  - don't crash when encountering `types.Invalid`
  - revise defer to use heap allocations when running a variable number of times
  - improve error messages for failed imports
  - improve "function redeclared" error
  - add globaldce pass to start of optimization pipeline
  - add support for debugging globals
  - implement RISC-V CSR operations as intrinsics
  - add support for CGO_ENABLED environment variable
  - do not emit debug info for extern globals (bugfix)
  - add support for interrupts
  - implement maps for arbitrary keys
  - interp: error location for "unknown GEP" error
  - wasm-abi: create temporary allocas in the entry block
* **cgo**
  - add support for symbols in `#define`
  - fix a bug in number tokenization
* **standard library**
  - `machine`: avoid bytes package in USB logic
  - `runtime`: fix external address declarations
  - `runtime`: provide implementation for `internal/bytealg.IndexByte`
* **targets**
  - `atsamd51`: fix volatile usage
  - `atsamd51`: fix ADC, updating to 12-bits precision
  - `atsamd51`: refactor SPI pin configuration to only look at pin numbers
  - `atsamd51`: switch UART to use new pin configuration
  - `atsamd51`: fix obvious bug in I2C code
  - `atsamd51`: use only the necessary UART interrupts
  - `atsamd51`: refactor I2C pin handling to auto-detect pin mode
  - `avr`: use a garbage collector
  - `fe310`: use CLINT peripheral for timekeeping
  - `fe310`: add support for PLIC interrupts
  - `fe310`: implement UART receive interrupts
  - `riscv`: support sleeping in QEMU
  - `riscv`: add bare-bones interrupt support
  - `riscv`: print exception PC and code
  - `wasm`: implement memcpy and memset
  - `wasm`: include wasi-libc
  - `wasm`: use wasi ABI for basic startup/stdout
* **boards**
  - `arduino`: make avrdude command line compatible with Windows
  - `arduino-nano`: add this board
  - `arduino-nano33`: fix UART1 and UART2
  - `circuitplay-bluefruit`: add this board
  - `digispark`: add clock speed and pin mappings
  - `gameboy-advance`: include compiler-rt in build
  - `gameboy-advance`: implement interrupt handler
  - `hifive1b`: add support for gdb subcommand
  - `pyportal`: add this board
  - `pyportal`: remove manual SPI pin mapping as now handled by default


0.11.0
---
* **command line**
  - add support for QEMU in `gdb` subcommand
  - use builtin Clang when building statically, dropping the clang-9 dependency
  - search for default serial port on both macOS and Linux
  - windows: support `tinygo flash` directly by using win32 wmi
* **compiler**
  - add location information to the IR checker
  - make reflection sidetables constant globals
  - improve error locations in goroutine lowering
  - interp: improve support for maps with string keys
  - interp: add runtime fallback for mapassign operations
* **standard library**
  - `machine`: add support for `SPI.Tx()` on play.tinygo.org
  - `machine`: rename `CPU_FREQUENCY` to `CPUFrequency()`
* **targets**
  - `adafruit-pybadge`: add Adafruit Pybadge
  - `arduino-nano33`: allow simulation on play.tinygo.org
  - `arduino-nano33`: fix default SPI pin numbers to be D13/D11/D12
  - `circuitplay-express`: allow simulation on play.tinygo.org
  - `hifive1-qemu`: add target for testing RISC-V bare metal in QEMU
  - `riscv`: fix heap corruption due to changes in LLVM 9
  - `riscv`: add support for compiler-rt
  - `qemu`: rename to `cortex-m-qemu`

0.10.0
---
* **command line**
  - halt GDB after flashing with `gdb` subcommand
  - fix a crash when using `-ocd-output`
  - add `info` subcommand
  - add `-programmer` flag
* **builder**
  - macos: use llvm@8 instead of just llvm in paths
  - add `linkerscript` key to target JSON files
  - write a symbol table when writing out the compiler-rt lib
  - make Clang header detection more robust
  - switch to LLVM 9
* **compiler**
  - fix interface miscompilation with reflect
  - fix miscompile of static goroutine calls to closures
  - fix `todo: store` panic
  - fix incorrect starting value for optimized allocations in a loop
  - optimize coroutines on non-Cortex-M targets
  - fix crash for programs which have heap allocations but never hit the GC
  - add support for async interface calls
  - fix inserting non-const values in a const global
  - interp: improve error reporting
  - interp: implement comparing ptrtoint to 0
* **cgo**
  - improve diagnostics
  - implement the constant parser (for `#define`) as a real parser
  - rename reserved field names such as `type`
  - avoid `"unsafe" imported but not used` error
  - include all enums in the CGo Go AST
  - add support for nested structs and unions
  - implement `#cgo CFLAGS`
* **standard library**
  - `reflect`: add implementation of array alignment
  - `runtime`: improve scheduler performance when no goroutines are queued
  - `runtime`: add blocking select
  - `runtime`: implement interface equality in non-trivial cases
  - `runtime`: add AdjustTimeOffset to update current time
  - `runtime`: only implement CountString for required platforms
  - `runtime`: use MSP/PSP registers for scheduling on Cortex-M
* **targets**
  - `arm`: add system timer registers
  - `atmega`: add port C GPIO support
  - `atsamd21`: correct handling of pins >= 32
  - `atsamd21`: i2s initialization fixes
  - `atsamd51`: fix clock init code
  - `atsamd51`: correct initialization for RTC
  - `atsamd51`: fix pin function selection
  - `atsamd51`: pin method cleanup
  - `atsamd51`: allow setting pin mode for each of the SPI pins
  - `atsamd51`: correct channel init and pin map for ADC based on ItsyBitsy-M4
  - `feather-m4`: add Adafruit Feather M4 board
  - `hifive1b`: add support for SPI1
  - `hifive1b`: fix compiling in simulation
  - `linux`: fix time on arm32
  - `metro-m4`: add support for Adafruit Metro M4 Express Airlift board
  - `metro-m4`: fixes for UART2
  - `pinetime-devkit0`: add support for the PineTime dev kit
  - `x9pro`: add support for this smartwatch
  - `pca10040-s132v6`: add support for SoftDevice
  - `pca10056-s140v7`: add support for SoftDevice
  - `arduino-nano33`: added SPI1 connected to NINA-W102 chip on Arduino Nano 33 IOT

0.9.0
---
* **command line**
  - implement 1200-baud UART bootloader reset when flashing boards that support
    it
  - flash using mass-storage device for boards that support it
  - implement `tinygo env`
  - add support for Windows (but not yet producing Windows binaries)
  - add Go version to `tinygo env`
  - update SVD files for up-to-date peripheral interfaces
* **compiler**
  - add `//go:align` pragma
  - fix bug related to type aliases
  - add support for buffered channels
  - remove incorrect reflect optimization
  - implement copying slices in init interpretation
  - add support for constant indices with a named type
  - add support for recursive types like linked lists
  - fix miscompile of function nil panics
  - fix bug related to goroutines
* **standard library**
  - `machine`: do not check for nil slices in `SPI.Tx`
  - `reflectlite`: add support for Go 1.13
  - `runtime`: implement `internal/bytealg.CountString`
  - `sync`: properly handle nil `New` func in `sync.Pool`
* **targets**
  - `arduino`: fix .bss section initialization
  - `fe310`: implement `Pin.Get`
  - `gameboy-advance`: support directly outputting .gba files
  - `samd`: reduce code size by avoiding reflection
  - `samd21`: do not hardcode pin numbers for peripherals
  - `stm32f103`: avoid issue with `time.Sleep` less than 200µs

0.8.0
---
* **command line**
  - fix parsing of beta Go versions
  - check the major/minor installed version of Go before compiling
  - validate `-target` flag better to not panic on an invalid target
* **compiler**
  - implement full slice expression: `s[:2:4]`
  - fix a crash when storing a linked list in an interface
  - fix comparing struct types by making type IDs more unique
  - fix some bugs in IR generation
  - add support for linked lists in reflect data
  - implement `[]rune` to string conversion
  - implement support for `go` on func values
* **standard library**
  - `reflect`: add support for named types
  - `reflect`: add support for `t.Bits()`
  - `reflect`: add basic support for `t.AssignableTo()`
  - `reflect`: implement `t.Align()`
  - `reflect`: add support for struct types
  - `reflect`: fix bug in `v.IsNil` and `v.Pointer` for addressable values
  - `reflect`: implement support for array types
  - `reflect`: implement `t.Comparable()`
  - `runtime`: implement stack-based scheduler
  - `runtime`: fix bug in the sleep queue of the scheduler
  - `runtime`: implement `memcpy` for Cortex-M
  - `testing`: implement stub `testing.B` struct
  - `testing`: add common test logging methods such as Errorf/Fatalf/Printf
* **targets**
  - `386`: add support for linux/386 syscalls
  - `atsamd21`: make SPI pins configurable so that multiple SPI ports can be
    used
  - `atsamd21`: correct issue with invalid first reading coming from ADC
  - `atsamd21`: add support for reset-to-bootloader using 1200baud over USB-CDC
  - `atsamd21`: make pin selection more flexible for peripherals
  - `atsamd21`: fix minimum delay in `time.Sleep`
  - `atsamd51`: fix minimum delay in `time.Sleep`
  - `nrf`: improve SPI write-only speed, by making use of double buffering
  - `stm32f103`: fix SPI frequency selection
  - `stm32f103`: add machine.Pin.Get method for reading GPIO values
  - `stm32f103`: allow board specific UART usage
  - `nucleo-f103rb`: add support for NUCLEO-F103RB board
  - `itsybitsy-m4`: add support for this board with a SAMD51 family chip
  - `cortex-m`: add support for `arm.SystemReset()`
  - `gameboy-advance`: add initial support for the GameBoy Advance
  - `wasm`: add `//go:wasm-module` magic comment to set the wasm module name
  - `wasm`: add syscall/js.valueSetIndex support
  - `wasm`: add syscall/js.valueInvoke support

0.7.1
---
* **targets**
  - `atsamd21`: add support for the `-port` flag in the flash subcommand

0.7.0
---
* **command line**
  - try more locations to find Clang built-in headers
  - add support for `tinygo test`
  - build current directory if no package is specified
  - support custom .json target spec with `-target` flag
  - use zversion.go to detect version of GOROOT version
  - make initial heap size configurable for some targets (currently WebAssembly
    only)
* **cgo**
  - add support for bitfields using generated getters and setters
  - add support for anonymous structs
* **compiler**
  - show an error instead of panicking on duplicate function definitions
  - allow packages like github.com/tinygo-org/tinygo/src/\* by aliasing it
  - remove `//go:volatile` support  
    It has been replaced with the runtime/volatile package.
  - allow poiners in map keys
  - support non-constant syscall numbers
  - implement non-blocking selects
  - add support for the `-tags` flag
  - add support for `string` to `[]rune` conversion
  - implement a portable conservative garbage collector (with support for wasm)
  - add the `//go:noinline` pragma
* **standard library**
  - `os`: add `os.Exit` and `syscall.Exit`
  - `os`: add several stubs
  - `runtime`: fix heap corruption in conservative GC
  - `runtime`: add support for math intrinsics where supported, massively
    speeding up some benchmarks
  - `testing`: add basic support for testing
* **targets**
  - add support for a generic target that calls `__tinygo_*` functions for
    peripheral access
  - `arduino-nano33`: add support for this board
  - `hifive1`: add support for this RISC-V board
  - `reelboard`: add e-paper pins
  - `reelboard`: add `PowerSupplyActive` to enable voltage for on-board devices
  - `wasm`: put the stack at the start of linear memory, to detect stack
    overflows

0.6.0
---
* **command line**
  - some portability improvements
  - make `$GOROOT` more robust and configurable
  - check for Clang at the Homebrew install location as fallback
* **compiler driver**
  - support multiple variations of LLVM commands, for non-Debian distributions
* **compiler**
  - improve code quality in multiple ways
  - make panic configurable, adding trap on panic
  - refactor many internal parts of the compiler
  - print all errors encountered during compilation
  - implement calling function values of a named type
  - implement returning values from blocking functions
  - allow larger-than-int values to be sent across a channel
  - implement complex arithmetic
  - improve hashmap support
  - add debuginfo for function arguments
  - insert nil checks on stores (increasing code size)
  - implement volatile operations as compiler builtins
  - add `//go:inline` pragma
  - add build tags for the Go stdlib version
* **cgo**
  - implement `char`, `enum` and `void*` types
  - support `#include` for builtin headers
  - improve typedef/struct/enum support
  - only include symbols that are necessary, for broader support
  - mark external function args as `nocapture`
  - implement support for some `#define` constants
  - implement support for multiple CGo files in a single package
- **standard library**
  - `machine`: remove microbit matrix (moved to drivers repository)
  - `machine`: refactor pins to use `Pin` type instead of `GPIO`
  - `runtime`: print more interface types on panic, including `error`
* **targets**
  - `arm`: print an error on HardFault (including stack overflows)
  - `atsamd21`: fix a bug in the ADC peripheral
  - `atsamd21`: add support for I2S
  - `feather-m0`: add support for this board
  - `nrf51`: fix a bug in I2C
  - `stm32f103xx`: fix a bug in I2C
  - `syscall`: implement `Exit` on unix
  - `trinket-m0`: add support for this board
  - `wasm`: make _main_ example smaller
  - `wasm`: don't cache wasm file in the server, for ease of debugging
  - `wasm`: work around bug #41508 that caused a deadlock while linking
  - `wasm`: add support for `js.FuncOf`

0.5.0
---
- **compiler driver**
  - use `wasm-ld` instead of `wasm-ld-8` on macOS
  - drop dependency on `llvm-ar`
  - fix linker script includes when running outside `TINYGOROOT`
- **compiler**
  - switch to LLVM 8
  - add support for the Go 1.12 standard library (Go 1.11 is still supported)
  - work around lack of escape analysis due to nil checks
  - implement casting named structs and pointers to them
  - fix int casting to use the source signedness
  - fix some bugs around `make([]T, …)` with uncommon index types
  - some other optimizations
  - support interface asserts in interp for "math/rand" support
  - resolve all func value targets at compile time (wasm-only at the moment)
- **cgo**
  - improve diagnostics
  - implement C `struct`, `union`, and arrays
  - fix CGo-related crash in libclang
  - implement `C.struct_` types
- **targets**
  - all baremetal: pretend to be linux/arm instead of js/wasm
  - `avr`: improve `uintptr` support
  - `cortexm`: implement memmove intrinsic generated by LLVM
  - `cortexm`: use the lld linker instead of `arm-none-eabi-ld`
  - `darwin`: use custom syscall package that links to libSystem.dylib
  - `microbit`: add blink example
  - `samd21`: support I2C1
  - `samd21`: machine/atsamd21: correct pad/pin handling when using both UART
     and USBCDC interfaces at same time
  - `stm32f4discovery`: add support for this board
  - `wasm`: support async func values
  - `wasm`: improve documentation and add extra example

0.4.1
---
- **compiler**
  - fix `objcopy` replacement to include the .data section in the firmware image
  - use `llvm-ar-7` on Linux to fix the Docker image

0.4.0
---
- **compiler**
  - switch to the hardfloat ABI on ARM, which is more widely used
  - avoid a dependency on `objcopy` (`arm-none-eabi-objcopy` etc.)
  - fix a bug in `make([]T, n)` where `n` is 64-bits on a 32-bit platform
  - adapt to a change in the AVR backend in LLVM 8
  - directly support the .uf2 firmware format as used on Adafruit boards
  - fix a bug when calling `panic()` at init time outside of the main package
  - implement nil checks, which results in a ~5% increase in code size
  - inline slice bounds checking, which results in a ~1% decrease in code size
- **targets**
  - `samd21`: fix a bug in port B pins
  - `samd21`: implement SPI peripheral
  - `samd21`: implement ADC peripheral
  - `stm32`: fix a bug in timekeeping
  - `wasm`: fix a bug in `wasm_exec.js` that caused corruption in linear memory
     when running on Node.js.

0.3.0
---
- **compiler**
  - remove old `-initinterp` flag
  - add support for macOS
- **cgo**
  - add support for bool/float/complex types
- **standard library**
  - `device/arm`: add support to disable/enable hardware interrupts
  - `machine`: add CPU frequency for nrf-based boards
  - `syscall`: add support for darwin/amd64
- **targets**
  - `circuitplay_express`: add support for this board
  - `microbit`: add regular pin constants
  - `samd21`: fix time function for goroutine support
  - `samd21`: add support for USB-CDC (serial over USB)
  - `samd21`: add support for pins in port B
  - `samd21`: add support for pullup and pulldown pins
  - `wasm`: add support for Safari in example


0.2.0
---
- **command line**
  - add version subcommand
- **compiler**
  - fix a bug in floating point comparisons with NaN values
  - fix a bug when calling `panic` in package initialization code
  - add support for comparing `complex64` and `complex128`
- **cgo**
  - add support for external globals
  - add support for pointers and function pointers
- **standard library**
  - `fmt`: initial support, `fmt.Println` works
  - `math`: support for most/all functions
  - `os`: initial support (only stdin/stdout/stderr)
  - `reflect`: initial support
  - `syscall`: add support for amd64, arm, and arm64