[MacPorts] #57612: clang does not respect -syslibroot when linking

[MacPorts]

#57612: clang does not respect -syslibroot when linking
---------------------+--------------------
  Reporter:  kencu   |      Owner:  (none)
      Type:  defect  |     Status:  new
  Priority:  Normal  |  Milestone:
 Component:  ports   |    Version:
Resolution:          |   Keywords:
      Port:          |
---------------------+--------------------

Comment (by mouse07410):

 Clang of Xcode-10.1 does not accept {{{-syslibroot}}} argument at all.
 That's what prevents {{gimp-print}}} from being built on Mojave:

 {{{
 :info:build /usr/bin/clang -r -keep_private_externs -nostdlib -o
 .libs/libgimpprint.1.1.3.dylib-master.o  print-lexmark.lo print-canon.lo
 print-dither.lo print-escp2.lo print-escp2-data.lo print-pcl.lo print-
 ps.lo print-util.lo print-color.lo print-weave.lo print-version.lo print-
 dither-matrices.lo && /usr/bin/clang -dynamiclib -flat_namespace
 -undefined suppress -o .libs/libgimpprint.1.1.3.dylib
 .libs/libgimpprint.1.1.3.dylib-master.o  -L/opt/local/lib -liconv -lm -lc
 -headerpad_max_install_names -syslibroot
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk
 -install_name /opt/local/lib/libgimpprint.1.dylib -compatibility_version 3
 -current_version 3.3
 :info:build clang: error: unknown argument: '-syslibroot'
 :info:build make[3]: *** [libgimpprint.la] Error 1
 . . . . .
 $ ll
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk
 lrwxr-xr-x  1 root  wheel  10 Oct 30 13:56
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk@
 -> MacOSX.sdk
 $ ll
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
 total 0
 drwxr-xr-x  7 root  wheel   224 Oct 18 08:52 ./
 drwxr-xr-x  4 root  wheel   128 Oct 30 13:57 ../
 -rw-r--r--  1 root  wheel   127 Aug 17 19:45 Entitlements.plist
 -rw-r--r--  1 root  wheel  1150 Aug 17 19:45 SDKSettings.json
 -rw-r--r--  1 root  wheel  1326 Aug 17 19:45 SDKSettings.plist
 drwxr-xr-x  3 root  wheel    96 Oct 18 08:52 System/
 drwxr-xr-x  7 root  wheel   224 Oct 18 08:52 usr/
 $
 }}}

 On an unrelated issue - even though I set Macports clang to be the
 default, this port insists on using {{{/usr/bin/clang}}}. How to remedy
 this???

-- 
Ticket URL: <https://trac.macports.org/ticket/57612#comment:22>
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