[MacPorts] #52082: flann 1.8.4 fails to build with gcc6

[MacPorts]

#52082: flann 1.8.4 fails to build with gcc6
----------------------+--------------------------------
 Reporter:  gnwiii@…  |      Owner:  macports-tickets@…
     Type:  defect    |     Status:  new
 Priority:  Normal    |  Milestone:
Component:  ports     |    Version:  2.3.4
 Keywords:  gcc6      |       Port:  flann
----------------------+--------------------------------
 {{{
 :info:build
 /opt/local/var/macports/build/_opt_local_var_macports_sources_svn.macports.org_trunk_dports_science_flann/flann/work/flann-1.8.4-src/src/cpp/flann/algorithms/kdtree_index.h:666:39:
 error: call of overloaded 'abs(flann::KDTreeIndex<flann::L2<float>
 >::ElementType)' is ambiguous
 }}}

 [https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=822717 Debian bug
 #822717] reports that the bug was fixed in flann-1.8.5 and provides a
 patch for 1.8.4.


 [https://github.com/mariusmuja/flann/commit/3645f0c30a47267e56e5acdecfc7bac2b76bc3d5
 patch on github]



 {{{
 ElementType span = abs(point[i]-leaf_point[i]);
 }}}

 needs to {{{#include <cmath>}}} and:

 {{{
 ElementType span = std::abs(point[i]-leaf_point[i]);
 }}}

 The macports build succeeds when I apply these changes to the interrupted
 build.

-- 
Ticket URL: <https://trac.macports.org/ticket/52082>
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