[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:                      |
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Comment (by bjax):

 I have had the same problem with macport since I guess 2.5 was released;
 an example is updating OpenSSL. Looks like my xcode-select is correct and
 command line tools are installed.

 I am running MacOS 10.12.6, Xcode 9.2.

 The SDK folder is at
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs;
 it contains two files:

 * MacOSX.sdk
 * MacOSX10.13.sdk

 Apparently Xcode ships with the next planned macOS SDK, "but it supports
 older ones" (I read somewhere while frantically searching for a fix),
 something I fail to comprehend.

 I'm having no problems with MacPorts 2.5.2 on the home OS 10.13 machine so
 it appears to be related with 10.12.

-- 
Ticket URL: <https://trac.macports.org/ticket/56619#comment:6>
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