Makefiles don't do comments, so these were forwarded into the variable.
*Most* users would expand the arguments to a shell where it'd be
ignored, but not all of them.
Contributes-To: https://github.com/RIOT-OS/RIOT/pull/18489
(This is also where the one version that is added here was removed).
It turns out that #18287 needs to be somewhat reverted.
The make behaviour requires use to add psuedomodules for packages
that are not compiled (ie header only).
The only difference from the revert is that the module is no longer
selected in Kconfig so it will match the modules used list.
There was a mismatch between Kconfig and make, after some digging it
appears that the make never used the emlearn module, only the package.
This removes the emlearn pseudomodule from make since nothing selects it
and removes the MODULE_EMLEARN from Kconfig to match the make dependency
resolution.
