[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 seanngpack):

 Replying to [comment:20 mouse07410]:
 > Found one problem: in addition to installing CLTools for Xcode-11, one
 must manually symlink:
 > {{{
 > $ sudo ln -s /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk
 > }}}
 >
 > Then everything works fine.

 I'm having issues with {{{ sudo port install gcc9}}} on Catalina & Xcode
 11 even after symbolic linking the 10.14 SDK. Are there any other steps
 after that?
 It may also be because I do not see a symbolic link generated?

 {{{
 Seans-MacBook:SDKs seanngpack$ ls -l
 total 0
 lrwxr-xr-x  1 root  wheel   15 Oct  8 17:19 MacOSX.sdk -> MacOSX10.15.sdk
 drwxr-xr-x  8 root  wheel  256 Oct 11 20:06 MacOSX10.14.sdk
 drwxr-xr-x  8 root  wheel  256 Aug 29 23:48 MacOSX10.15.sdk
 Seans-BMW-MacBook:SDKs seanngpack$
 }}}

-- 
Ticket URL: <https://trac.macports.org/ticket/59113#comment:28>
MacPorts <https://www.macports.org/>
Ports system for macOS