Add support for building with MOLD linker

[lrusak]

This adds support for using the mold linker, similar to how we support the GOLD linker.

This isn't enabled by default so shouldn't be much concern. You cannot have both GOLD_SUPPORT and MOLD_SUPPORT enabled at the same time though there isn't anything stopping you from doing so.

ref: https://github.com/rui314/mold

There is a few packages that don't compile with MOLD and I plan on submitting bug reports for those.

[vpeter4]

Why using extra mold patch file if adding flags to make command line works the same (as indicated in comment above in Makefile).
make ${PKG_MAKE_OPTS_HOST} CFLAGS="${CFLAGS}" CXXFLAGS="${CXXFLAGS}"

[lrusak]

Why using extra mold patch file if adding flags to make command line works the same (as indicated in comment above in Makefile).

make ${PKG_MAKE_OPTS_HOST} CFLAGS="${CFLAGS}" CXXFLAGS="${CXXFLAGS}"

Good catch, thanks. I went through a couple iterations and cleaned the package up a bit.

[lrusak]

Merge?

[CvH]

otherwise looks good

[SupervisedThinking]

IMHO the package template is pretty much straight forward if it comes to this topic:

# Copyright (C) 2018-present Team LibreELEC (https://libreelec.tv)

https://github.com/LibreELEC/LibreELEC.tv/blob/master/packages/packages.mk.template#L2

[SupervisedThinking]

Well well well - what's the deal with this PR now? Couldn't we just bring the copyright header in line with the current standards, get this merged & figure a proper way out afterwards? Or should this pretty useful improvement rotten?

[lrusak]

merge?

[heitbaum]

Should be -

[CvH]

afaik this PR has several shortcomings (not working for ARM) that are fixed at #6875

No idea if we want to merge this and #6875 as "patch" ontop or just supersede this pr with #6875.

[CvH]

superseded by #6875