[MacPorts] #59391: icu @65.1 fails to build on 10.9

[MacPorts]

#59391: icu @65.1 fails to build on 10.9
---------------------+------------------------
  Reporter:  jmroot  |      Owner:  ryandesign
      Type:  defect  |     Status:  assigned
  Priority:  Normal  |  Milestone:
 Component:  ports   |    Version:
Resolution:          |   Keywords:  mavericks
      Port:  icu     |
---------------------+------------------------

Comment (by erikbs):

 I am also on 10.9 and encountered this problem. Even though I have set
 clang 9.0 (`mp-clang-9.0`) as my default compiler (and also llvm 9.0 as my
 default llvm), MacPorts chose to use the one from Xcode 6.2 instead:

 {{{
 :debug:configure Preferred compilers: clang macports-clang-9.0 macports-
 clang-8.0 macports-clang-7.0 macports-clang-6.0 macports-clang-5.0
 macports-clang-3.7 macports-clang-3.4
 :debug:configure Using compiler 'Xcode Clang'
 […]
 :debug:configure CC='/usr/bin/clang'
 […]
 /Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/cstddef:55:21:
 note: 'std::max_align_t' declared here
 }}}

 The path `/Library/Developer/CommandLineTools` belongs to the Xcode
 command line tools, which have not been updated for Mavericks in years. I
 examined the file mentioned, and just as the compiler output says, there
 is no definition of a `max_align_t` type in there. It is, however, defined
 in the `std` namespace, just as the compiler suggests. Xcode 6.2’s clang
 is apparently based on LLVM 3.5.

 Then I looked into the version that llvm/clang 9.0 provides, i.e.
 `/opt/local/libexec/llvm-9.0/include/c++/v1/cstddef`, and in it I found
 these lines:
 {{{
 #if defined(__CLANG_MAX_ALIGN_T_DEFINED) || defined(_GCC_MAX_ALIGN_T) || \
     defined(__DEFINED_max_align_t) || defined(__NetBSD__)
 // Re-use the compiler's <stddef.h> max_align_t where possible.
 using ::max_align_t;
 #else
 typedef long double max_align_t;
 #endif
 }}}

 So the fix did make it into more recent versions of clang then and `icu`
 built just fine with the `configure.compiler` option set, but why does
 MacPorts ignore my compiler choice?

-- 
Ticket URL: <https://trac.macports.org/ticket/59391#comment:4>
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