[Dev] [PATCH] libremakepkg: fix building packages requring a rw startdir

[bill-auger]

only reverting that change is not enough to address the issue
though - we should also need to apply the patch gnutoo
suggested; because right now the kernels do not build
out-of-the-box with the standard tools - that should not be the
case for such a critical base package

i was hoping to avoid gnutoo's change which reverts something
lukeshu did months ago; because the change is more drastic and it
seems to have been done for a valuable reason

for now i suppose we need at the very least to add a comment to
the kernels PKGBUILD, making it clear that this package will not
build with the standard tools, but requires the nonsystemd
version of libretools, which does not contain the change that
lukeshu made to mount the /startdir read-only - that itself
seems like it was probably an oversight

if we do not apply gnutoo's patch to libretools, then the
nonsystemd version of libretools should also be made to mount
the /startdir read-only - in any case, that they should behave
the same so that the package builds out-of-the-box and we dont
need to document such quirky caveats