Hello, I'm trying to cross compile with arm-none-eabi-gcc on an Ubuntu x64 build machine.

My CMake toolchain file contains the following flags:
mcpu=cortex-m4 -mthumb -mfloat-abi=soft -fdata-sections -ffunction-sections \
--specs=rdimon.specs -lgcc -lc -lm -lrdimon
I invoke CMake with:
cmake -DCMAKE_TOOLCHAIN_FILE=arm-none-eabi-gcc-mcu.cmake \
cmake --build build/
I get implicit declaration errors relating to clock_gettime(), sigsetjmp(), siglongjmp() and other signal functions.
These are linux specific functions and so are obviously not present on a bare-metal machine.

How do I resolve these errors?

Ryan McClue, Sydney