This roughly restores the order of operation from Spack 0.20,
where where `AutotoolsPackage.setup_build_environment` would
override the env variable set in `setup_platform_environment` on
macOS.

This roughly restores the order of operation from Spack 0.20,
where where `AutotoolsPackage.setup_build_environment` would
override the env variable set in `setup_platform_environment` on
macOS.

This roughly restores the order of operation from Spack 0.20,
where where `AutotoolsPackage.setup_build_environment` would
override the env variable set in `setup_platform_environment` on
macOS.

This roughly restores the order of operation from Spack 0.20,
where where `AutotoolsPackage.setup_build_environment` would
override the env variable set in `setup_platform_environment` on
macOS.

This roughly restores the order of operation from Spack 0.20,
where where `AutotoolsPackage.setup_build_environment` would
override the env variable set in `setup_platform_environment` on
macOS.

This roughly restores the order of operation from Spack 0.20,
where where `AutotoolsPackage.setup_build_environment` would
override the env variable set in `setup_platform_environment` on
macOS.

The deps were added in spack#40945 to make it work on macOS 11, because the
old configure scripts only detect macOS 10. Apparently people the
autoreconf script caused issues, later fixed in spack#41057. However, also
with that fix, things are incorrect, cause people now report:

```
libtool: You should recreate aclocal.m4 with macros from libtool 2.4.7
libtool: and run autoconf again.
```

I did not check what that error is about exactly, but it looks like
Spack's `def autoreconf` step does way less than the `autgen.sh` script
provided in the source tarball.

HOWEVER, all this is unnecessary, because the underlying issue was
already fixed long ago, it's just that it regressed at some point, but
it's back in place since spack#41205, therefore, get rid of all this madness.

The deps were added in #40945 to make it work on macOS 11, because the
old configure scripts only detect macOS 10. Apparently people reported the
autoreconf script caused issues, later fixed in #41057. However, also
with that fix, things are incorrect, cause people now report:

```
libtool: You should recreate aclocal.m4 with macros from libtool 2.4.7
libtool: and run autoconf again.
```

HOWEVER, all this is unnecessary, because the underlying issue was
already fixed long ago, it's just that it regressed at some point, but
it's back in place since #41205.

The deps were added in spack#40945 to make it work on macOS 11, because the
old configure scripts only detect macOS 10. Apparently people reported the
autoreconf script caused issues, later fixed in spack#41057. However, also
with that fix, things are incorrect, cause people now report:

```
libtool: You should recreate aclocal.m4 with macros from libtool 2.4.7
libtool: and run autoconf again.
```

HOWEVER, all this is unnecessary, because the underlying issue was
already fixed long ago, it's just that it regressed at some point, but
it's back in place since spack#41205.

The deps were added in spack#40945 to make it work on macOS 11, because the
old configure scripts only detect macOS 10. Apparently people reported the
autoreconf script caused issues, later fixed in spack#41057. However, also
with that fix, things are incorrect, cause people now report:

```
libtool: You should recreate aclocal.m4 with macros from libtool 2.4.7
libtool: and run autoconf again.
```

HOWEVER, all this is unnecessary, because the underlying issue was
already fixed long ago, it's just that it regressed at some point, but
it's back in place since spack#41205.

This roughly restores the order of operation from Spack 0.20,
where where `AutotoolsPackage.setup_build_environment` would
override the env variable set in `setup_platform_environment` on
macOS.