Instead of using `weak` function definitions, this PR handles
default implementations using `PROVIDES_x` defines, allowing
for cpus/pm realted modules to use their own implementations.
- Copied the relevant parts of mipshal.mk from the toolchain
- Cleaned up CFLAGS and more in Makefile.include
- Added empty syscalls implementation which can be used to interface
with the UHI system
- Added a note on why -std=gnu99 is necessary for this CPU presently
Compilation for pic32mx and pic32mz did not include the path
to cpu/mips_pic32_common/include. Also,
cpu/mips_pic32_common/Makefile.include was never parsed. It was
found that mips32r2_common and mips_pic32_common are both defining
similar parameters for linkers which cause issues if both
Makefile.include get parsed.
Signed-off-by: Francois Berder <francois.berder@imgtec.com>
