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.
- Optimise ROTable accesses and interface
This includes some refinements to the ROTable cache which remove the linker cludges on the CROSS_COMPILE builds. Also keyhole tweaks to some of the Lua VM code to implrove runtimes.
I also noticed some compile time warnings during the build; the change to uz_unzip.c doesn't impact the compiled code, but does remove the compiler warnings.