Fix aarch/arm64 Architecture Issues

[jxmx]

This pull request addresses two things:

• Fixed the architecture mismatch in BASE_ARCH=aarch64 is Ignored #239 by adding a statement to read the basic config in before generating the board-related configuration
• A better fix for the logic on when qemu-arm-static isn't needed (e.g. building an aarch64 image on an aarch64 system). This replaces my old pull qemu-arm-static isn't needed when already on an arm64 box #228

[guysoft]

Hey, before I merge this I want to try and take all the logic out to a function and add a unit test, this area has been getting lots of attention and testing it is a little complex, I think. unit test would help out. so didn't forget it yet

[guysoft]

Ok, I put that section of code in to a unit test.
The tested options are:

    # aarch64 host
    # ["aarch64:armv7l:gentoo"]="not using qemu"
    ["aarch64:armv7l:ubuntu"]="using qemu-arm-static"
    # ["aarch64:armhf:gentoo"]="not using qemu"
    ["aarch64:armhf:ubuntu"]="using qemu-arm-static"
    ["aarch64:aarch64:gentoo"]="not using qemu"
    ["aarch64:aarch64:ubuntu"]="not using qemu"
    ["aarch64:arm64:gentoo"]="not using qemu"
    ["aarch64:arm64:ubuntu"]="not using qemu"

What target are you trying to build to on aarch64? And what distribution (if docker then its debian/Ubuntu)?

[jxmx]

I'm not sure I'm fully understanding what you're trying to do. However I've tested my code changes on both aarch64 and amd64 generating aarch64 PI images. No Docker.

[guysoft]

What I am doing is adding a unit test. It takes the code in the src/custompios script and tests all inputs to make ure they work correctly. Try not to focus on the code, but what you actually want it to do. If you are running on aarch64 and building aarch64, you dont need qemu-aarch64-static, no emulation is required.
I think the change is not required there. Since I ran the unit test with all the possibilities and they do want I expect, the question is do you want a different behavior?
2.
Only the change in src/build seems like its tackling an issue:

What its saying is that you need is to source the distro/config before AND after. It might make more sense only to get the BASE_BOARD variable.

Here is the execution order documentation:
https://github.com/guysoft/CustomPiOS/wiki/CustomPiOS-internals#execution-scripts-order

nightly_build_scripts/custompios_nightly_build
    ${CUSTOM_PI_OS_PATH}/build_custom_os "${WORKSPACE_SUFFIX}"
        ${DIR}/build "$1"
            source ${CUSTOM_PI_OS_PATH}/config "${1}" "${EXTRA_BOARD_CONFIG}" ${@}
            source ${CUSTOM_OS_PATH}/custompios ${@}

What this PR is suggesting is:

nightly_build_scripts/custompios_nightly_build
    ${CUSTOM_PI_OS_PATH}/build_custom_os "${WORKSPACE_SUFFIX}"
        ${DIR}/build "$1"
            source ${DISTRO}/config ${@} <-- SOURCE HERE            
            source ${CUSTOM_PI_OS_PATH}/config "${1}" "${EXTRA_BOARD_CONFIG}" ${@} <-- AND HERE because source ${DISTRO}/config  is sourced at the end here too.
            source ${CUSTOM_OS_PATH}/custompios ${@}

[jxmx]

Without my patch, src/custompios will try to use qemu-arm-static on an aarch64 box to build an aarch64 Pi image.