Fails to build on Ruby 2.1

[jasonmp85]

I don't have a ton of time to look into this (sorry!) and am not even sure where the canonical version of this gem lives (yours is the most accessible/maintained), but…

With Ruby 2.1 and a brew-installed gsl 1.15, I get these errors (and many warnings, but ignoring those) installing the gem:

linalg.c:74:28: error: read-only variable is not assignable
    RBASIC(omatrix)->klass = cgsl_matrix_LU;
    ~~~~~~~~~~~~~~~~~~~~~~ ^
linalg.c:695:28: error: read-only variable is not assignable
    RBASIC(mdecomp)->klass = cgsl_matrix_QR;
    ~~~~~~~~~~~~~~~~~~~~~~ ^
linalg.c:707:28: error: read-only variable is not assignable
    RBASIC(mdecomp)->klass = cgsl_matrix_LQ;
    ~~~~~~~~~~~~~~~~~~~~~~ ^
linalg.c:734:33: error: read-only variable is not assignable
      RBASIC(argv[itmp])->klass = cgsl_vector_tau;
      ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
linalg.c:743:33: error: read-only variable is not assignable
      RBASIC(argv[itmp])->klass = cgsl_vector_tau;
      ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
linalg.c:1631:23: error: read-only variable is not assignable
    RBASIC(vA)->klass = cgsl_matrix_QRPT;
    ~~~~~~~~~~~~~~~~~ ^
linalg.c:1638:23: error: read-only variable is not assignable
    RBASIC(vA)->klass = cgsl_matrix_PTLQ;
    ~~~~~~~~~~~~~~~~~ ^
7 errors generated.
make: *** [linalg.o] Error 1

AFAIK, Ruby 2.1 no longer allows assignment to klass in this manner (it's now declared as const). brianmario/escape_utils#48 appears to solve a similar problem in that codebase, so maybe the same approach could work here. I'd dig deeper into this, but I really just need a normal variable so I'll write my own Box-Muller in Ruby until the gsl bindings support Ruby 2.1.

[romanbsd]

Unfortunately I don't have time to dig into it :(

[jjk-jacky]

FYI, facing this today, I came up with this ugly patch to fix it.

[zampino]

I could gem install 'rb-gsl' under ruby 2.1.1. rb-gsl is maintained by SciRuby https://github.com/SciRuby/rb-gsl