So these special remotes are always supported.
IIRC these build flags were added because the dep chains were a bit too
long, or perhaps because the libraries were not available in Debian stable,
or something like that. That was long ago, those reasons no longer apply,
and users get confused when builtin special remotes are not available, so
it seems best to remove the build flags now.
If this does cause a problem it can be reverted of course..
This commit was sponsored by Jochen Bartl on Patreon.
Seems 13.11 was not being used for a while, but 14.27 works.
For some reason, stack was getting confused when I set the magicmime
flag on the command line, but setting it in stack.yaml didn't confuse
it. Ugh.
Unfortunately, the autobuilder is using an old version of OSX, and
cannot use ghc newer than the one in lts-13.11. Newer ghc versions use a
libc symbol that is not available.
Since the main stack.yaml has been updated to a newer lts, and just
substituting in lts-13.11 no longer works due to other dependency
issues, it's simplest to use a separate one for the OSX build.
Hopefully this is temporary, and the autobuilder gets updated.
