* Fix gcc recipe for RHEL7.
+ It appears that macOS related changes to the gcc recipe broke gcc on RHEL7.
This bug manifests as `libstdc++.so: undefined reference to libiconv` when gcc
is used.
+ Fixes#13452 by moving
`--with-libiconv-prefix={0}'.format(spec['libiconv'].prefix)` into the darwin
OS section of the configuration.
+ Change qualification of `depends_on(libiconv)` to limit dependency to macOS.
* Replace deprecated 'setup_environment' with 'setup_run_environment'.
* Fix cut and paste error.
* Rename 'run_env' to just 'env'.
ffb4e02a53