[MacPorts] #69867: legacy-support headers should work with later SDK versions

[MacPorts]

#69867: legacy-support headers should work with later SDK versions
-----------------------------+-----------------------
  Reporter:  fhgwright       |      Owner:  fhgwright
      Type:  defect          |     Status:  assigned
  Priority:  Low             |  Milestone:
 Component:  ports           |    Version:  2.9.3
Resolution:                  |   Keywords:
      Port:  legacy-support  |
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Comment (by fhgwright):

 In [changeset:"3b29576cd0eda9d9c45ca241cb806c616ff19df1/macports-legacy-
 support" 3b29576cd0eda9d9c45ca241cb806c616ff19df1/macports-legacy-support]
 (master):
 {{{
 #!ConfigurableCommitTicketReference repository="macports-legacy-support"
 revision="3b29576cd0eda9d9c45ca241cb806c616ff19df1"
 Fix 10.6- builds with 10.14+ SDKs.

 Beginning with the 10.14 SDK, AvailabilityInternal.h uses the
 __has_include() feature without checking whether it's available.  So
 we add the usual default definition when it's not.

 Re: https://trac.macports.org/ticket/69867

 TESTED:
 Tested on 10.4-10.5 ppc, 10.5-10.6 ppc (i386 Rosetta), 10.4-10.6 i386,
 10.5-12.x x86_64, and 11.x-14.x arm64.  Tested against all 10.4-14.x
 SDKs, using the headerinfo manual test (from a subsequent commit).
 All target/SDK combinations where the SDK supports the CPU
 architecture work correctly, including all SDKs on Intel
 architectures.  Only 10.4-10.6 SDKs support ppc, and only 11.x+ SDKs
 support arm64.
 }}}

-- 
Ticket URL: <https://trac.macports.org/ticket/69867#comment:12>
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