[MacPorts] #50800: fix for cairo build failures against Xcode 7.3 linker when /uer/local/lib is absent

[MacPorts]

#50800: fix for cairo build failures against Xcode 7.3 linker when /uer/local/lib
is absent
------------------------------------+--------------------------------
  Reporter:  howarth.at.macports@…  |      Owner:  macports-tickets@…
      Type:  defect                 |     Status:  new
  Priority:  Normal                 |  Milestone:
 Component:  ports                  |    Version:  2.3.4
Resolution:                         |   Keywords:
      Port:  cairo                  |
------------------------------------+--------------------------------

Comment (by howarth.at.macports@…):

 Since the build fails on Xcode 7.3 when /usr/local/lib is absent due
 failure to detect the pthread support...


 {{{
 ./cairo-mutex-impl-private.h:262:3: error: "XXX: No mutex implementation
 found. Cairo will not work with multiple threads. Define CAIRO_NO_MUTEX to
 1
       to acknowledge and accept this limitation and compile cairo without
 thread-safety support."
 }}}

 it seems unnecessary to bump the revision.

-- 
Ticket URL: <https://trac.macports.org/ticket/50800#comment:1>
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