Fix build-time segfault on OSX (fixes #188)
Fix build-time segfault on OSX (fixes #188)

timholy/Images.jl,benmoran/Images.jl,twadleigh/Images.jl,twadleigh/Images.jl,zhmz90/Images.jl,c42f/Images.jl,zhmz90/Images.jl,rened/Images.jl,angi2/Images.jl,cdsousa/Images.jl,c42f/Images.jl,cdsousa/Images.jl,JuliaPackageMirrors/Images.jl,benmoran/Images.jl,rened/Images.jl,angi2/Images.jl