[MacPorts] #61866: base uses incorrect SDK for Big Sur 11.1 and Xcode 12.3

[MacPorts]

#61866: base uses incorrect SDK for Big Sur 11.1 and Xcode 12.3
---------------------+--------------------
  Reporter:  mf2k    |      Owner:  (none)
      Type:  defect  |     Status:  new
  Priority:  Normal  |  Milestone:
 Component:  base    |    Version:  2.6.99
Resolution:          |   Keywords:
      Port:          |
---------------------+--------------------

Comment (by MaddTheSane):

 Attempting to build `git +svn` results in a build failure with
 `subversion-perlbindings-5.28` with the following errors:

 {{{
 :info:build clang: warning: no such sysroot directory:
 '/Library/Developer/CommandLineTools/SDKs/MacOSX11.0.sdk' [-Wmissing-
 sysroot]
 :info:build In file included from
 subversion/bindings/swig/perl/libsvn_swig_perl/swigutil_pl.c:24:
 :info:build /opt/local/include/apr-1/apr.h:165:10: fatal error:
 'sys/types.h' file not found
 :info:build #include <sys/types.h>
 :info:build          ^~~~~~~~~~~~~
 :info:build 1 error generated.
 :info:build make: ***
 [subversion/bindings/swig/perl/libsvn_swig_perl/swigutil_pl.lo] Error 1
 }}}

 Creating a symbolic link for 11.0 (`sudo ln -s MacOSX11.1.sdk
 MacOSX11.0.sdk`) makes it build farther, but then it runs into #61523.

-- 
Ticket URL: <https://trac.macports.org/ticket/61866#comment:18>
MacPorts <https://www.macports.org/>
Ports system for macOS