First time on M5, and quite enthousiastic.
Unfortunately, I am unable to compile examples under macOS 10.11.6, Arduino IDE 1.6.6

I followed setup instructions here: https://m5stack.github.io/m5-docs/#/en/quick_start/m5core/m5stack_core_get_started_Arduino_MacOS?id=step1-install-arduino-ide

but fixed library path according to a message posted on the forum: https://dl.espressif.com/dl/package_esp32_index.json

Then, I tried to compile (or compile & upload) "Hello World": here is the message I get:

WARNING: Spurious .git folder in 'M5Stack' library
Build options changed, rebuilding all
In file included from /Users/simon/Documents/Arduino/hardware/espressif/esp32/tools/xtensa-esp32-elf/xtensa-esp32-elf/include/dirent.h:6:0,
from /Users/simon/Documents/Arduino/hardware/espressif/esp32/libraries/FS/src/vfs_api.h:24,
from /Users/simon/Documents/Arduino/hardware/espressif/esp32/libraries/FS/src/vfs_api.cpp:15:
/Users/simon/Documents/Arduino/hardware/espressif/esp32/tools/xtensa-esp32-elf/xtensa-esp32-elf/include/sys/dirent.h:10:2: error: #error "<dirent.h> not supported"
#error "<dirent.h> not supported"
^
exit status 1
Error compiling.

Any suggestion ?