[MacPorts] #63360: libsdl2: fails to build due to unknown builtin '__builtin_bswap16'

[MacPorts]

#63360: libsdl2: fails to build due to unknown builtin '__builtin_bswap16'
----------------------+----------------------
  Reporter:  mrkapqa  |      Owner:  jmroot
      Type:  defect   |     Status:  assigned
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:  2.7.1
Resolution:           |   Keywords:  lion
      Port:  libsdl2  |
----------------------+----------------------

Comment (by kencu):

 according to <https://packages.macports.org/libsdl2/> everything from
 10.11 thru 10.15 failed.

 so we need to blacklist the clangs up to what is in 10.15, and that should
 do it.

 Josh is around. Probably already working on it.

-- 
Ticket URL: <https://trac.macports.org/ticket/63360#comment:4>
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