The PR removed the bulk of non-newlib headers from the NodeMCU source base.
app/libc has now been cut down to the bare minimum overrides to shadow the
corresponding functions in the SDK's libc. The old c_xyz.h headerfiles have been
nuked in favour of the standard <xyz.h> headers, with a few exceptions over in
sdk-overrides. Again, shipping a libc.a without headers is a terrible thing to do. We're
still living on a prayer that libc was configured the same was as a default-configured
xtensa gcc toolchain assumes it is. That part I cannot do anything about, unfortunately,
but it's no worse than it has been before.
This enables our source files to compile successfully using the standard header files,
and use the typical malloc()/calloc()/realloc()/free(), the strwhatever()s and
memwhatever()s. These end up, through macro and linker magic, mapped to the
appropriate SDK or ROM functions.
* I2C driver speed-up, i2c.SLOW, i2c.FAST and user-defined speed selection
* - Multiple buses (up to 10) with different speeds on each bus
- Standard(Slow, 100kHz), Fast(400kHz) and FastPlus(1MHz) modes or an
arbitrary clock speed
- Sharing SDA line over multiple I²C buses to save available pins
- GPIO16 pin can be used as SCL pin, but it does not support clock
stretching and selected bus will be limited to FAST speed.
* Dynamic memory allocation, error checks, simplification, timing tweaks.
* Separated the code of old driver for better compatibility and simplicity
* Change of driver interface
* Add bus status check in setup(); simplify getDC(); remove unnesessary lines in ACK read/write
* Fix for moved doc file and trailing whitespaces