[MacPorts] #59113: gcc: cannot find systems headers with Xcode 11

[MacPorts]

#59113: gcc: cannot find systems headers with Xcode 11
-----------------------------+--------------------
  Reporter:  abyrvalk        |      Owner:  (none)
      Type:  defect          |     Status:  new
  Priority:  Normal          |  Milestone:
 Component:  ports           |    Version:
Resolution:                  |   Keywords:
      Port:  gcc7 gcc8 gcc9  |
-----------------------------+--------------------

Comment (by mouse07410):

 > I suggest installing the latest CLTools (from Xcode 11) as they contain
 the 10.14 SDK as well.

 I confirm that it does. But there seem to be some problems. After
 installing CLTools for Xcode-11, I get
 {{{
 $ xcrun --show-sdk-path
 /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk
 $ xcrun --show-sdk-platform-path
 xcodebuild: error: SDK
 "/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk" cannot be
 located.
 xcrun: error: unable to lookup item 'PlatformPath' in SDK
 '/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk'
 $ clang -v
 Apple clang version 11.0.0 (clang-1100.0.33.8)
 Target: x86_64-apple-darwin18.7.0
 Thread model: posix
 InstalledDir:
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
 $ xcodebuild -showsdks
 iOS SDKs:
         iOS 13.0                        -sdk iphoneos13.0

 iOS Simulator SDKs:
         Simulator - iOS 13.0            -sdk iphonesimulator13.0

 macOS SDKs:
         DriverKit 19.0                  -sdk driverkit.macosx19.0
         macOS 10.15                     -sdk macosx10.15

 tvOS SDKs:
         tvOS 13.0                       -sdk appletvos13.0

 tvOS Simulator SDKs:
         Simulator - tvOS 13.0           -sdk appletvsimulator13.0

 watchOS SDKs:
         watchOS 6.0                     -sdk watchos6.0

 watchOS Simulator SDKs:
         Simulator - watchOS 6.0         -sdk watchsimulator6.0

 $ xcrun --sdk macosx clang -v
 Apple clang version 11.0.0 (clang-1100.0.33.8)
 Target: x86_64-apple-darwin18.7.0
 Thread model: posix
 InstalledDir:
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
 $ xcrun --sdk macosx10.15 clang -v
 Apple clang version 11.0.0 (clang-1100.0.33.8)
 Target: x86_64-apple-darwin18.7.0
 Thread model: posix
 InstalledDir:
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
 $ xcrun --sdk macosx10.14 clang -v
 xcodebuild: error: SDK "macosx10.14" cannot be located.
 xcrun: error: sh -c
 '/Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild -sdk
 macosx10.14 -find clang 2> /dev/null' failed with exit code 16384: (null)
 (errno=No such file or directory)
 xcrun: error: unable to find utility "clang", not a developer tool or in
 PATH
 $
 }}}

 Could you maybe comment on the above?

-- 
Ticket URL: <https://trac.macports.org/ticket/59113#comment:19>
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