[MacPorts] #71618: qt5-qtbase @5.15.15_2 does not build on macOS High Sierra, version 10.13.6, because of ld error (and cryptic warnings?)

[MacPorts]

#71618: qt5-qtbase @5.15.15_2 does not build on macOS High Sierra, version 10.13.6,
because of ld error (and cryptic warnings?)
-------------------------+---------------------------------
  Reporter:  ballapete   |      Owner:  MarcusCalhoun-Lopez
      Type:  defect      |     Status:  assigned
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:  2.10.5
Resolution:              |   Keywords:  highsierra
      Port:  qt5-qtbase  |
-------------------------+---------------------------------

Comment (by ballapete):

 `port -v upgrade qt5-qtbase configure.ldflags-append="-undefined
 dynamic_lookup"` leads to

 {{{
 Undefined symbols for architecture x86_64:
   "__availability_version_check", referenced from:
       ___isPlatformVersionAtLeast in
 libclang_rt.osx.a(os_version_check.c.o)
       __initializeAvailabilityCheck in
 libclang_rt.osx.a(os_version_check.c.o)
 ld: symbol(s) not found for architecture x86_64
 }}}

 because the linker did not learn it:

 {{{
 /opt/local/bin/clang++-mp-17 -stdlib=libc++ -headerpad_max_install_names
 -fapplication-extension  -arch x86_64 -isysroot
 /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-
 min=10.13 -Wl,-rpath, at executable_path/../Frameworks
 -Wl,-rpath, at loader_path/Frameworks -single_module -dynamiclib
 -compatibility_version  5.15 -current_version   5.15.15 -install_name
 /opt/local/libexec/qt5/lib/QtCore.framework/Versions/5/QtCore -o QtCore
 ...  -framework DiskArbitration -framework IOKit -lm -framework AppKit
 -framework Security -framework ApplicationServices -framework CoreServices
 -framework CoreFoundation -framework Foundation -lz -ldouble-conversion
 -licui18n -licuuc -licudata -L/opt/local/lib -lpcre2-16 -lzstd
 -lgthread-2.0 -lglib-2.0 -lintl
 }}}

-- 
Ticket URL: <https://trac.macports.org/ticket/71618#comment:5>
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