A cross-platform code builder and the missing library manager (Atmel AVR & SAM, Freescale Kinetis, Nordic nRF51, NXP LPC, ST STM32, TI MSP430 & Tiva, Teensy, Arduino, mbed, libOpenCM3, etc.)
PlatformIO is independent from the platform where it is running (the only requirement is Python, which exists pretty much everywhere).