[MacPorts] #42969: eigen: clang build fix

[MacPorts]

#42969: eigen: clang build fix
--------------------------+--------------------------------
 Reporter:  ryandesign@…  |      Owner:  macports-tickets@…
     Type:  defect        |     Status:  new
 Priority:  Normal        |  Milestone:
Component:  ports         |    Version:  2.2.1
 Keywords:  haspatch      |       Port:  eigen
--------------------------+--------------------------------
 eigen fails to build with clang on Mavericks with this error:

 {{{
 /opt/local/var/macports/build/_Users_rschmidt_macports_dports_math_eigen/eigen/work
 /eigen-eigen-b23437e61a07/Eigen/src/QR/QrInstantiations.cpp:36:22: error:
 explicit instantiation cannot have a storage class
 template static void ei_tridiagonal_qr_step(float* , float* , int, int,
 float* , int);
          ~~~~~~~     ^
 /opt/local/var/macports/build/_Users_rschmidt_macports_dports_math_eigen/eigen/work
 /eigen-eigen-b23437e61a07/Eigen/src/QR/QrInstantiations.cpp:37:22: error:
 explicit instantiation cannot have a storage class
 template static void ei_tridiagonal_qr_step(double* , double* , int, int,
 double* , int);
          ~~~~~~~     ^
 /opt/local/var/macports/build/_Users_rschmidt_macports_dports_math_eigen/eigen/work
 /eigen-eigen-b23437e61a07/Eigen/src/QR/QrInstantiations.cpp:38:22: error:
 explicit instantiation cannot have a storage class
 template static void ei_tridiagonal_qr_step(float* , float* , int, int,
 std::complex<float>* , int);
          ~~~~~~~     ^
 /opt/local/var/macports/build/_Users_rschmidt_macports_dports_math_eigen/eigen/work
 /eigen-eigen-b23437e61a07/Eigen/src/QR/QrInstantiations.cpp:39:22: error:
 explicit instantiation cannot have a storage class
 template static void ei_tridiagonal_qr_step(double* , double* , int, int,
 std::complex<double>* , int);
          ~~~~~~~     ^
 4 errors generated.
 make[2]: *** [Eigen/CMakeFiles/Eigen2.dir/src/QR/QrInstantiations.cpp.o]
 Error 1
 }}}

 Attached is a patch to fix this, [https://lists.macosforge.org/pipermail
 /macports-users/2014-March/034951.html submitted on the mailing list] by
 René J.V. Bertin.

-- 
Ticket URL: <https://trac.macports.org/ticket/42969>
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