[MacPorts] #60039: freecad @0.18.4_0+gcc9: configure failure, can't find boost

[MacPorts]

#60039: freecad @0.18.4_0+gcc9: configure failure, can't find boost
----------------------------+-------------------------
  Reporter:  informatimago  |      Owner:  Schamschula
      Type:  defect         |     Status:  assigned
  Priority:  Normal         |  Milestone:
 Component:  ports          |    Version:  2.6.2
Resolution:                 |   Keywords:
      Port:  freecad        |
----------------------------+-------------------------

Comment (by ryandesign):

 Replying to [comment:3 Schamschula]:
 > Currently freecad still requires Python 2.7.

 freecad 0.18.4 fails to build on the buildbot on all versions of macOS
 with this error:

 {{{
 -- Could NOT find Boost (missing: python27) (found version "1.71.0")
 -- Could NOT find Boost (missing: python2) (found version "1.71.0")
 CMake Error at
 /opt/local/share/cmake-3.17/Modules/FindPackageHandleStandardArgs.cmake:164
 (message):
   Could NOT find Boost (missing: python) (found version "1.71.0")
 }}}

 Note that boost's default python variant was
 [changeset:6008e784c15e0b352960eb892c14dd721bdcb1ac/macports-ports changed
 from python27 to python37 last year] and then
 [changeset:e0abbf5c0e309ebc1a0c9ffbec8b9e92782fe3b9/macports-ports to
 python38 this month]. If freecad requires that boost be installed with the
 python27 variant, use the require_active_variants procedure from the
 active_variants 1.1 portgroup to indicate that. That won't enable the
 buildbot to build the port, but it will at least provide the user with a
 better error message that shows them how to work around the problem.

-- 
Ticket URL: <https://trac.macports.org/ticket/60039#comment:8>
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