R=golang-dev, rsc CC=golang-dev https://golang.org/cl/747041
lots of missing parts, but builds and can call dlls, see a sample code in syscall_mingw.go R=rsc CC=golang-dev https://golang.org/cl/218042
* move memory code into $GOOS-specific directory. * allow printing of static strings < 256 bytes. (dynamic strings will bump maxstring as they are allocated.) * use cgo2c for runtime.mal. R=r, dho CC=golang-dev https://golang.org/cl/186143
R=rsc CC=golang-dev https://golang.org/cl/176066
