[MacPorts] #56619: I ran "sudo port selfupdate" and now I cannot install any ports without an error

[MacPorts]

#56619: I ran "sudo port selfupdate" and now I cannot install any ports without an
error
---------------------------------+--------------------
  Reporter:  JulioDavidMartinez  |      Owner:  (none)
      Type:  defect              |     Status:  new
  Priority:  Normal              |  Milestone:
 Component:  base                |    Version:  2.5.2
Resolution:                      |   Keywords:
      Port:                      |
---------------------------------+--------------------

Comment (by bjax):

 I opened Xcode 9.2, built a project or two, and closed it. Xcode seemed
 happy.

 But again:
 {{{
 $ sudo port -d  install opens
 DEBUG: Copying /Users/bjax/Library/Preferences/com.apple.dt.Xcode.plist to
 /opt/local/var/macports/home/Library/Preferences
 DEBUG: Changing to port directory:
 /opt/local/var/macports/sources/rsync.macports.org/release/tarballs/ports/devel/openssl
 DEBUG: OS darwin/16.7.0 (Mac OS X 10.12) arch i386
 DEBUG: Reading variant descriptions from
 /opt/local/var/macports/sources/rsync.macports.org/release/tarballs/ports/_resources/port1.0/variant_descriptions.conf
 DEBUG: Sourcing PortGroup muniversal 1.0 from
 /opt/local/var/macports/sources/rsync.macports.org/release/tarballs/ports/_resources/port1.0/group/muniversal-1.0.tcl
 Error: Unable to determine location of a macOS SDK.
 DEBUG: Unable to determine location of a macOS SDK.
     while executing
 "portconfigure::configure_get_sdkroot ${configure.sdk_version}"
     invoked from within
 "set configure.sdkroot [portconfigure::configure_get_sdkroot
 ${configure.sdk_version}]"
     ("uplevel" body line 1)
     invoked from within
 "uplevel #0 set $optionName $option_defaults($optionName)"
     (procedure "default_check" line 11)
     invoked from within
 "default_check configure.sdkroot {} r"
     (read trace on "configure.sdkroot")
     invoked from within
 "if {${configure.sdkroot} ne ""} {
     configure.args-append   '-isysroot ${configure.sdkroot}' \
                             -Wl,-syslibroot,${configu..."
     (file "Portfile" line 64)
     invoked from within
 "source Portfile"
     invoked from within
 "$workername eval {source Portfile}"
     (procedure "mportopen" line 50)
     invoked from within
 "mportopen $porturl [array get options] [array get requested_variations]"
 Error: Unable to open port: can't read "configure.sdkroot": Unable to
 determine location of a macOS SDK.
 }}}

-- 
Ticket URL: <https://trac.macports.org/ticket/56619#comment:8>
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