py36-scikit-learn fails to build due to incorrect env quoting

[gjaeger (Gregor Jäger)]

Error: Failed to build py36-scikit-learn: command execution failed
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-scikit-learn/py36-scikit-learn/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets to report a bug.
Error: Processing of port py36-scikit-learn failed

:info:build ValueError: bad string (mismatched " quotes?)
:info:build Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-scikit-learn/py36-scikit-learn/work/scikit-learn-0.21.3" && /opt/local/Library/Frameworks/Python.framework/Versions/3.6/bin/python3.6 setup.py --no-user-cfg build
:info:build Exit code: 1
:error:build Failed to build py36-scikit-learn: command execution failed
:debug:build Error code: CHILDSTATUS 2694 1
:debug:build Backtrace: command execution failed
:debug:build     while executing
:debug:build "system {*}$notty {*}$nice $fullcmdstring"
:debug:build     invoked from within
:debug:build "command_exec build"
:debug:build     (procedure "portbuild::build_main" line 8)
:debug:build     invoked from within
:debug:build "$procedure $targetname"
:error:build See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-scikit-learn/py36-scikit-learn/main.log for details.

[jmroot (Joshua Root)]

In f55ef926c18f5fb27c672e660d9e982e14834f86/macports-ports (master):

py-scikit-learn: fix env quoting

Closes: #59266