[MacPorts] #58998: port @2.5.99 fails to build a port - in this case ldns.

[MacPorts]

#58998: port @2.5.99 fails to build a port - in this case ldns.
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  Reporter:  snowflake  |      Owner:  (none)
      Type:  defect     |     Status:  new
  Priority:  Normal     |  Milestone:
 Component:  base       |    Version:  2.5.99
Resolution:             |   Keywords:
      Port:             |
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Comment (by satraul):

 After investigating, I think the problem is that:
 1. in the configure phase, macports is decides to use the 'Xcode Clang'
 compiler (/usr/bin/clang) which we resolve to CommandLineTools
 2. in the build phase, libtool is called which should be called with the
 CommandLineTools SDK path in {{{-isysroot}}} but isn't. it's empty. should
 be something like
 {{{-isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX10.11.sdk}}}.
 which is why this warning pops up:
 {{{
 clang: warning: no such sysroot directory: '-I/opt/local/include'
 }}}

 3. build fails because it couldn't find SDK headers (stdio.h)

 I've no idea why 2 happens, my guess that it's related to problems with
 libtool as discussed here: https://trac.macports.org/ticket/57612

 Your guess of that the CLT is out of date is plausible to why
 {{{-isysroot}}} is empty. It might be that libtool finds the SDK path
 using {{{xcrun}}} which is known to output an empty string on old versions
 (though it should be a non-zero ouput)

-- 
Ticket URL: <https://trac.macports.org/ticket/58998#comment:3>
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