gama: fix build on aarch64-darwin

+2
+2
pkgs/applications/science/geometry/gama/default.nix
··· 12 13 nativeBuildInputs = [ texinfo zip ]; 14 15 nativeCheckInputs = [ octave libxml2 ]; 16 doCheck = true; 17
··· 12 13 nativeBuildInputs = [ texinfo zip ]; 14 15 + env.CXXFLAGS = lib.optionalString stdenv.cc.isClang "-include sstream"; 16 + 17 nativeCheckInputs = [ octave libxml2 ]; 18 doCheck = true; 19