STM: fix ARMClang sct files, using proper -E command

[0xc0170]

Summary of changes

This is required for ARMClang, otherwise there is an error with unknown command. I forgot to fix this in the previous PR where I added CMake files.

Impact of changes

Migration actions required

Documentation

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Pull request type

[x] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[x] No Tests required for this change (E.g docs only update)
[] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

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[ciarmcom]

@0xc0170, thank you for your changes.
@ARMmbed/team-st-mcd @ARMmbed/mbed-os-maintainers please review.

[0xc0170]

Fixed both as requested

[rajkan01]

LGTM

[0xc0170]

CI started

[mbed-ci]

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jobs	Status
jenkins-ci/mbed-os-ci_unittests	✔️
jenkins-ci/mbed-os-ci_cmake-example-ARM	✔️
jenkins-ci/mbed-os-ci_cmake-example-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_build-greentea-ARM	✔️
jenkins-ci/mbed-os-ci_build-greentea-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_build-cloud-example-ARM	✔️
jenkins-ci/mbed-os-ci_build-example-ARM	✔️
jenkins-ci/mbed-os-ci_build-cloud-example-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_build-example-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_dynamic-memory-usage	✔️
jenkins-ci/mbed-os-ci_cmake-example-test	✔️
jenkins-ci/mbed-os-ci_greentea-test	✔️
jenkins-ci/mbed-os-ci_cloud-client-pytest	✔️

[jeromecoutant]

Back to this PR...
Could you explain why this line has to be added ?
It is a duplication with files in https://github.com/ARMmbed/mbed-os/tree/master/tools/cmake/cores ?

[0xc0170]

armclang linker needs it to execute preprocessor, explained in the ARMClang documentation . I can't find the exact link but quickly found:

Use the first line in the scatter file to specify a preprocessor command that the linker invokes to process the file.

If you do not have this first line, linker would not invoke anything else.