[MacPorts] #44355: opencv @2.4.9 - build failure: Undefined symbols for architecture x86_64: "_main", referenced from: start in crt1.10.6.o (And probable fix)

[MacPorts]

#44355: opencv @2.4.9 - build failure: Undefined symbols for architecture x86_64:
"_main", referenced from:       start in crt1.10.6.o (And probable fix)
-------------------------------------------+-------------------------------
 Reporter:  g.litenstein@…                 |      Owner:  macports-
     Type:  defect                         |  tickets@…
 Priority:  Normal                         |     Status:  new
Component:  ports                          |  Milestone:
 Keywords:  undefined, symbols, crt1.10.6  |    Version:  2.3.1
                                           |       Port:  opencv
-------------------------------------------+-------------------------------
 I've been trying to get OpenCV to compile for over a week now and have
 been hitting this error no matter what I did. Google hadn't been very
 helpful until I found a post explaining that when you're not compiling an
 executable, this error will appear unless the "-c" flag is used.

 {{{
 Undefined symbols for architecture x86_64:
   "_main", referenced from:
       start in crt1.10.6.o
 ld: symbol(s) not found for architecture x86_64
 collect2: error: ld returned 1 exit status
 make[2]: *** [modules/core/precomp.hpp.gch/opencv_core_Release.gch] Error
 1
 make[2]: Leaving directory
 `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_opencv/opencv/work/build'
 make[1]: *** [modules/core/CMakeFiles/pch_Generate_opencv_core.dir/all]
 Error 2
 make[1]: *** Waiting for unfinished jobs....
 Undefined symbols for architecture x86_64:
   "_main", referenced from:
       start in crt1.10.6.o
 ld: symbol(s) not found for architecture x86_64
 collect2: error: ld returned 1 exit status
 make[2]: *** [modules/flann/precomp.hpp.gch/opencv_flann_Release.gch]
 Error 1
 make[2]: Leaving directory
 `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_opencv/opencv/work/build'
 make[1]: *** [modules/flann/CMakeFiles/pch_Generate_opencv_flann.dir/all]
 Error 2
 make[1]: Leaving directory
 `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_opencv/opencv/work/build'
 make: *** [all] Error 2
 make: Leaving directory
 `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_opencv/opencv/work/build'
 Command failed:  cd
 "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_opencv/opencv/work/opencv-2.4.9/../build"
 && /usr/bin/make -j2 -w all
 Exit code: 2
 Error: org.macports.build for port opencv returned: command execution
 failed
 DEBUG: Error code: CHILDSTATUS 8137 2
 DEBUG: Backtrace: command execution failed
     while executing
 "system -nice 0 $fullcmdstring"
     ("eval" body line 1)
     invoked from within
 "eval system $notty $nice \$fullcmdstring"
     invoked from within
 "command_exec build"
     (procedure "portbuild::build_main" line 8)
     invoked from within
 "portbuild::build_main org.macports.build"
     ("eval" body line 1)
     invoked from within
 "eval $procedure $targetname"
 Warning: targets not executed for opencv: org.macports.activate
 org.macports.build org.macports.destroot org.macports.install
 Please see the log file for port opencv for details:
 /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_opencv/opencv/main.log
 To report a bug, follow the instructions in the guide:
     http://guide.macports.org/#project.tickets
 Error: Processing of port opencv failed
 }}}

 After a bit of hunting in the port, I got to the file
 "opencv-2.4.9/cmake/OpenCVPCHSupport.cmake" and in there added said flag
 to three different lines, which resulted in the port finally building
 properly. (Patch attached)

-- 
Ticket URL: <https://trac.macports.org/ticket/44355>
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