Kirkstone backport ld is lld fixes

[jaskij]

According to suggestions in #841 , backport:

• https://github.com/kraj/meta-clang/commit/6ecaea06d5e6e7ed0a39b4c019fc485f18e1ce55
• https://github.com/kraj/meta-clang/commit/7419c1f4e13187311870785a11e8cffee2c640e6
• https://github.com/kraj/meta-clang/commit/0f31c0b29580825af8700e484b984a8824a31a4f

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