Turns out we had a bunch of silly dependencies on libc headers that are
not included with freestanding compilers. Fix all this and change the
CFLAGS to exclude libc headers and only include the built-in compiler
path.
Add our own versions of assert.h, errno.h, limits.h, and move malloc.h
and string.h together into a new path used as -isystem, so these headers
can be included using #include <>.
Remove a bunch of other dependencies in third-party code.
Add a strnlen function.
Disable building the libfdt overlay code for now, as it needs a strtoul
implementation. We can throw that in if/when we decide to use overlays.
Signed-off-by: Hector Martin <marcan@marcan.st>
heapblock is a simple `sbrk` style implementation, also useful as an
"endless" decompression buffer. dlmalloc is used on top as a malloc
implementation.
This also changes how the Python side manages its heap. We still use a
python-side malloc implementation (since this is faster), and we put the
Python heap at the m1n1 heap + 128MB, without allocating it.
Hopefully this should never step on anything m1n1 neads, and avoids
having to manage freeing across Python script calls.
Signed-off-by: Hector Martin <marcan@marcan.st>
