diff --git a/pkgs/applications/science/chemistry/octopus/default.nix b/pkgs/applications/science/chemistry/octopus/default.nix
index f30954367cf7..adb31d326509 100644
--- a/pkgs/applications/science/chemistry/octopus/default.nix
+++ b/pkgs/applications/science/chemistry/octopus/default.nix
@@ -2,7 +2,7 @@
 , libyaml, libxc, fftw, blas, lapack, gsl, netcdf, arpack, autoreconfHook
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "octopus";
diff --git a/pkgs/applications/science/machine-learning/shogun/default.nix b/pkgs/applications/science/machine-learning/shogun/default.nix
index 33871df87f33..031ca55a0480 100644
--- a/pkgs/applications/science/machine-learning/shogun/default.nix
+++ b/pkgs/applications/science/machine-learning/shogun/default.nix
@@ -13,7 +13,7 @@
 assert pythonSupport -> pythonPackages != null;
 assert opencvSupport -> opencv != null;
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 let
   pname = "shogun";
diff --git a/pkgs/applications/science/math/R/default.nix b/pkgs/applications/science/math/R/default.nix
index 836ce004fff2..617a18265371 100644
--- a/pkgs/applications/science/math/R/default.nix
+++ b/pkgs/applications/science/math/R/default.nix
@@ -9,7 +9,7 @@
 , static ? false
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   name = "R-3.6.3";
diff --git a/pkgs/applications/science/math/giac/default.nix b/pkgs/applications/science/math/giac/default.nix
index be3c1e6dcc88..ea9c921f19e1 100644
--- a/pkgs/applications/science/math/giac/default.nix
+++ b/pkgs/applications/science/math/giac/default.nix
@@ -5,7 +5,7 @@
 }:
 
 assert enableGUI -> libGLU != null && libGL != null && xorg != null && fltk != null;
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "giac${lib.optionalString enableGUI "-with-xcas"}";
diff --git a/pkgs/applications/science/math/gmsh/default.nix b/pkgs/applications/science/math/gmsh/default.nix
index 8ece2e7819cf..946beff8003f 100644
--- a/pkgs/applications/science/math/gmsh/default.nix
+++ b/pkgs/applications/science/math/gmsh/default.nix
@@ -1,7 +1,7 @@
 { stdenv, fetchurl, cmake, blas, lapack, gfortran, gmm, fltk, libjpeg
 , zlib, libGL, libGLU, xorg, opencascade-occt }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "gmsh";
diff --git a/pkgs/applications/science/math/sage/sage-env.nix b/pkgs/applications/science/math/sage/sage-env.nix
index c0dfeef1119b..626e1bf1ea92 100644
--- a/pkgs/applications/science/math/sage/sage-env.nix
+++ b/pkgs/applications/science/math/sage/sage-env.nix
@@ -54,7 +54,7 @@
 , less
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 # This generates a `sage-env` shell file that will be sourced by sage on startup.
 # It sets up various environment variables, telling sage where to find its
diff --git a/pkgs/applications/science/math/sage/sage-with-env.nix b/pkgs/applications/science/math/sage/sage-with-env.nix
index 77bc65c2be12..87c1e07f5307 100644
--- a/pkgs/applications/science/math/sage/sage-with-env.nix
+++ b/pkgs/applications/science/math/sage/sage-with-env.nix
@@ -23,7 +23,7 @@
 }:
 
 # lots of segfaults with (64 bit) blas
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 # Wrapper that combined `sagelib` with `sage-env` to produce an actually
 # executable sage. No tests are run yet and no documentation is built.
diff --git a/pkgs/applications/science/math/sage/sagelib.nix b/pkgs/applications/science/math/sage/sagelib.nix
index 92b4e8efa2ec..830d806a8bcd 100644
--- a/pkgs/applications/science/math/sage/sagelib.nix
+++ b/pkgs/applications/science/math/sage/sagelib.nix
@@ -53,7 +53,7 @@
 , pplpy
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 # This is the core sage python package. Everything else is just wrappers gluing
 # stuff together. It is not very useful on its own though, since it will not
diff --git a/pkgs/build-support/alternatives/blas/default.nix b/pkgs/build-support/alternatives/blas/default.nix
index bce0c7af2bc1..45fb69eddb7d 100644
--- a/pkgs/build-support/alternatives/blas/default.nix
+++ b/pkgs/build-support/alternatives/blas/default.nix
@@ -1,7 +1,7 @@
 { lib, stdenv
 , lapack-reference, openblasCompat, openblas
-, is64bit ? false
-, blasProvider ? if is64bit then openblas else openblasCompat }:
+, isILP64 ? false
+, blasProvider ? if isILP64 then openblas else openblasCompat }:
 
 let
   blasFortranSymbols = [
@@ -31,12 +31,12 @@ let
                        else stdenv.hostPlatform.extensions.sharedLibrary;
 
 
-  is64bit = blasProvider.blas64 or false;
+  isILP64 = blasProvider.blas64 or false;
   blasImplementation = lib.getName blasProvider;
 
 in
 
-assert is64bit -> (blasImplementation == "openblas" && blasProvider.blas64) || blasImplementation == "mkl";
+assert isILP64 -> (blasImplementation == "openblas" && blasProvider.blas64) || blasImplementation == "mkl";
 
 stdenv.mkDerivation {
   pname = "blas";
@@ -49,7 +49,7 @@ stdenv.mkDerivation {
   };
 
   passthru = {
-    inherit is64bit;
+    inherit isILP64;
     provider = blasProvider;
     implementation = blasImplementation;
   };
@@ -134,6 +134,6 @@ Libs: -L$out/lib -lcblas
 EOF
 '' + stdenv.lib.optionalString (blasImplementation == "mkl") ''
   mkdir -p $out/nix-support
-  echo 'export MKL_INTERFACE_LAYER=${lib.optionalString is64bit "I"}LP64,GNU' > $out/nix-support/setup-hook
+  echo 'export MKL_INTERFACE_LAYER=${lib.optionalString isILP64 "I"}LP64,GNU' > $out/nix-support/setup-hook
 '');
 }
diff --git a/pkgs/build-support/alternatives/lapack/default.nix b/pkgs/build-support/alternatives/lapack/default.nix
index 75dc2ae3b343..c90eb43494d8 100644
--- a/pkgs/build-support/alternatives/lapack/default.nix
+++ b/pkgs/build-support/alternatives/lapack/default.nix
@@ -1,7 +1,7 @@
 { lib, stdenv
 , lapack-reference, openblasCompat, openblas
-, is64bit ? false
-, lapackProvider ? if is64bit then openblas else openblasCompat }:
+, isILP64 ? false
+, lapackProvider ? if isILP64 then openblas else openblasCompat }:
 
 let
 
@@ -14,7 +14,7 @@ let
 
 in
 
-assert is64bit -> (lapackImplementation == "openblas" && lapackProvider.blas64) || lapackImplementation == "mkl";
+assert isILP64 -> (lapackImplementation == "openblas" && lapackProvider.blas64) || lapackImplementation == "mkl";
 
 stdenv.mkDerivation {
   pname = "lapack";
@@ -27,7 +27,7 @@ stdenv.mkDerivation {
   };
 
   passthru = {
-    inherit is64bit;
+    inherit isILP64;
     provider = lapackProvider;
     implementation = lapackImplementation;
   };
@@ -108,6 +108,6 @@ Libs: -L$out/lib -llapacke
 EOF
 '' + stdenv.lib.optionalString (lapackImplementation == "mkl") ''
   mkdir -p $out/nix-support
-  echo 'export MKL_INTERFACE_LAYER=${lib.optionalString is64bit "I"}LP64,GNU' > $out/nix-support/setup-hook
+  echo 'export MKL_INTERFACE_LAYER=${lib.optionalString isILP64 "I"}LP64,GNU' > $out/nix-support/setup-hook
 '');
 }
diff --git a/pkgs/development/compilers/julia/1.3.nix b/pkgs/development/compilers/julia/1.3.nix
index 49dc17a27f45..b67a78b4a5ab 100644
--- a/pkgs/development/compilers/julia/1.3.nix
+++ b/pkgs/development/compilers/julia/1.3.nix
@@ -12,7 +12,7 @@
 , CoreServices, ApplicationServices
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 with stdenv.lib;
 
@@ -88,7 +88,7 @@ stdenv.mkDerivation rec {
       "SHELL=${stdenv.shell}"
 
       "USE_SYSTEM_BLAS=1"
-      "USE_BLAS64=${if blas.is64bit then "1" else "0"}"
+      "USE_BLAS64=${if blas.isILP64 then "1" else "0"}"
 
       "USE_SYSTEM_LAPACK=1"
 
diff --git a/pkgs/development/compilers/julia/shared.nix b/pkgs/development/compilers/julia/shared.nix
index 92e3d4a5c14b..29ac41150506 100644
--- a/pkgs/development/compilers/julia/shared.nix
+++ b/pkgs/development/compilers/julia/shared.nix
@@ -22,7 +22,7 @@
 
 with stdenv.lib;
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 let
   dsfmtVersion = "2.2.3";
@@ -137,7 +137,7 @@ stdenv.mkDerivation rec {
       "SHELL=${stdenv.shell}"
 
       "USE_SYSTEM_BLAS=1"
-      "USE_BLAS64=${if blas.is64bit then "1" else "0"}"
+      "USE_BLAS64=${if blas.isILP64 then "1" else "0"}"
 
       "USE_SYSTEM_LAPACK=1"
 
diff --git a/pkgs/development/interpreters/octave/default.nix b/pkgs/development/interpreters/octave/default.nix
index 4d2bf40b3292..06d69ed8117f 100644
--- a/pkgs/development/interpreters/octave/default.nix
+++ b/pkgs/development/interpreters/octave/default.nix
@@ -53,7 +53,7 @@
 , darwin
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   version = "5.2.0";
@@ -125,12 +125,12 @@ stdenv.mkDerivation rec {
   enableParallelBuilding = true;
 
   # See https://savannah.gnu.org/bugs/?50339
-  F77_INTEGER_8_FLAG = if blas.is64bit then "-fdefault-integer-8" else "";
+  F77_INTEGER_8_FLAG = if blas.isILP64 then "-fdefault-integer-8" else "";
 
   configureFlags = [
     "--with-blas=blas"
     "--with-lapack=lapack"
-    (if blas.is64bit then "--enable-64" else "--disable-64")
+    (if blas.isILP64 then "--enable-64" else "--disable-64")
   ]
     ++ (if stdenv.isDarwin then [ "--enable-link-all-dependencies" ] else [ ])
     ++ stdenv.lib.optionals enableReadline [ "--enable-readline" ]
diff --git a/pkgs/development/libraries/fflas-ffpack/default.nix b/pkgs/development/libraries/fflas-ffpack/default.nix
index 16a9e3e79d45..bc84039a9aa2 100644
--- a/pkgs/development/libraries/fflas-ffpack/default.nix
+++ b/pkgs/development/libraries/fflas-ffpack/default.nix
@@ -2,7 +2,7 @@
 , gmpxx
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "fflas-ffpack";
diff --git a/pkgs/development/libraries/linbox/default.nix b/pkgs/development/libraries/linbox/default.nix
index 6d25cb459870..2217996acdbc 100644
--- a/pkgs/development/libraries/linbox/default.nix
+++ b/pkgs/development/libraries/linbox/default.nix
@@ -10,7 +10,7 @@
 , withSage ? false # sage support
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "linbox";
diff --git a/pkgs/development/libraries/qrupdate/default.nix b/pkgs/development/libraries/qrupdate/default.nix
index f6c16583ad75..424502dce0d4 100644
--- a/pkgs/development/libraries/qrupdate/default.nix
+++ b/pkgs/development/libraries/qrupdate/default.nix
@@ -18,7 +18,7 @@ stdenv.mkDerivation {
           -e 's,^LAPACK=.*,LAPACK=-L${lapack}/lib -llapack,' \
           Makeconf
     ''
-    + stdenv.lib.optionalString blas.is64bit
+    + stdenv.lib.optionalString blas.isILP64
     ''
       sed -i Makeconf -e '/^FFLAGS=.*/ s/$/-fdefault-integer-8/'
     '';
diff --git a/pkgs/development/libraries/science/math/arpack/default.nix b/pkgs/development/libraries/science/math/arpack/default.nix
index a5fbb679df5b..0829557d0f3d 100644
--- a/pkgs/development/libraries/science/math/arpack/default.nix
+++ b/pkgs/development/libraries/science/math/arpack/default.nix
@@ -27,7 +27,7 @@ stdenv.mkDerivation {
 
   cmakeFlags = [
     "-DBUILD_SHARED_LIBS=ON"
-    "-DINTERFACE64=${optionalString blas.is64bit "1"}"
+    "-DINTERFACE64=${optionalString blas.isILP64 "1"}"
   ];
 
   preCheck = if stdenv.isDarwin then ''
diff --git a/pkgs/development/libraries/science/math/ipopt/default.nix b/pkgs/development/libraries/science/math/ipopt/default.nix
index 647fd82ec0e9..97374fb0d477 100644
--- a/pkgs/development/libraries/science/math/ipopt/default.nix
+++ b/pkgs/development/libraries/science/math/ipopt/default.nix
@@ -1,6 +1,6 @@
 { stdenv, fetchurl, unzip, blas, lapack, gfortran }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "ipopt";
diff --git a/pkgs/development/libraries/science/math/scalapack/default.nix b/pkgs/development/libraries/science/math/scalapack/default.nix
index d20219860296..1cf9c2ed8d53 100644
--- a/pkgs/development/libraries/science/math/scalapack/default.nix
+++ b/pkgs/development/libraries/science/math/scalapack/default.nix
@@ -2,7 +2,7 @@
 , gfortran, mpi, blas, lapack
 } :
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "scalapack";
diff --git a/pkgs/development/libraries/science/math/scs/default.nix b/pkgs/development/libraries/science/math/scs/default.nix
index 2dcb47f11baa..3820f2b95275 100644
--- a/pkgs/development/libraries/science/math/scs/default.nix
+++ b/pkgs/development/libraries/science/math/scs/default.nix
@@ -1,6 +1,6 @@
 { stdenv, fetchFromGitHub, blas, lapack, gfortran, fixDarwinDylibNames }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "scs";
diff --git a/pkgs/development/libraries/science/math/suitesparse/4.2.nix b/pkgs/development/libraries/science/math/suitesparse/4.2.nix
index 34a1fb7ad9e6..b1c1202c5780 100644
--- a/pkgs/development/libraries/science/math/suitesparse/4.2.nix
+++ b/pkgs/development/libraries/science/math/suitesparse/4.2.nix
@@ -1,7 +1,7 @@
 { stdenv, fetchurl, gfortran, blas, lapack }:
 
 let
-  int_t = if blas.is64bit then "int64_t" else "int32_t";
+  int_t = if blas.isILP64 then "int64_t" else "int32_t";
 in
 stdenv.mkDerivation rec {
   version = "4.2.1";
diff --git a/pkgs/development/libraries/science/math/suitesparse/4.4.nix b/pkgs/development/libraries/science/math/suitesparse/4.4.nix
index b2b7e666b7ef..81a80c920b53 100644
--- a/pkgs/development/libraries/science/math/suitesparse/4.4.nix
+++ b/pkgs/development/libraries/science/math/suitesparse/4.4.nix
@@ -6,7 +6,7 @@ let
   version = "4.4.4";
   name = "suitesparse-${version}";
 
-  int_t = if blas.is64bit then "int64_t" else "int32_t";
+  int_t = if blas.isILP64 then "int64_t" else "int32_t";
   SHLIB_EXT = stdenv.hostPlatform.extensions.sharedLibrary;
 in
 stdenv.mkDerivation {
diff --git a/pkgs/development/libraries/science/math/suitesparse/default.nix b/pkgs/development/libraries/science/math/suitesparse/default.nix
index 48177987a7a2..f0480e1e2381 100644
--- a/pkgs/development/libraries/science/math/suitesparse/default.nix
+++ b/pkgs/development/libraries/science/math/suitesparse/default.nix
@@ -44,7 +44,7 @@ stdenv.mkDerivation rec {
     "BLAS=-lblas"
     "LAPACK=-llapack"
     "MY_METIS_LIB=-lmetis"
-  ] ++ stdenv.lib.optionals blas.is64bit [
+  ] ++ stdenv.lib.optionals blas.isILP64 [
     "CFLAGS=-DBLAS64"
   ] ++ stdenv.lib.optionals enableCuda [
     "CUDA_PATH=${cudatoolkit}"
diff --git a/pkgs/development/libraries/science/math/superlu/default.nix b/pkgs/development/libraries/science/math/superlu/default.nix
index 05ceb21387d3..ff59297bd839 100644
--- a/pkgs/development/libraries/science/math/superlu/default.nix
+++ b/pkgs/development/libraries/science/math/superlu/default.nix
@@ -1,7 +1,7 @@
 { stdenv, fetchurl, cmake,
   gfortran, blas, lapack}:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   version = "5.2.1";
diff --git a/pkgs/development/libraries/sundials/2.x.nix b/pkgs/development/libraries/sundials/2.x.nix
index 08cbd52ba394..b54e537fb823 100644
--- a/pkgs/development/libraries/sundials/2.x.nix
+++ b/pkgs/development/libraries/sundials/2.x.nix
@@ -8,7 +8,7 @@
 , gfortran
 , lapackSupport ? true }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "sundials";
diff --git a/pkgs/development/libraries/sundials/default.nix b/pkgs/development/libraries/sundials/default.nix
index 8ed8d6cfcb55..46cf437d72ca 100644
--- a/pkgs/development/libraries/sundials/default.nix
+++ b/pkgs/development/libraries/sundials/default.nix
@@ -7,7 +7,7 @@
 , gfortran
 , lapackSupport ? true }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "sundials";
diff --git a/pkgs/development/ocaml-modules/lacaml/default.nix b/pkgs/development/ocaml-modules/lacaml/default.nix
index e4da2216a83d..23b38e469b4b 100644
--- a/pkgs/development/ocaml-modules/lacaml/default.nix
+++ b/pkgs/development/ocaml-modules/lacaml/default.nix
@@ -1,7 +1,7 @@
 { stdenv, fetchFromGitHub, darwin, ocaml, findlib, dune, base, stdio, lapack, blas }:
 
 assert stdenv.lib.versionAtLeast (stdenv.lib.getVersion ocaml) "4.05.0";
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "ocaml${ocaml.version}-lacaml";
diff --git a/pkgs/development/ocaml-modules/owl/default.nix b/pkgs/development/ocaml-modules/owl/default.nix
index c84743a8da52..b306ee9ce6d2 100644
--- a/pkgs/development/ocaml-modules/owl/default.nix
+++ b/pkgs/development/ocaml-modules/owl/default.nix
@@ -11,7 +11,7 @@
 , npy
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 assert blas.implementation == "openblas" && lapack.implementation == "openblas";
 
 buildDunePackage rec {
diff --git a/pkgs/development/python-modules/cvxopt/default.nix b/pkgs/development/python-modules/cvxopt/default.nix
index 9266f406b151..2b6d1b4d2484 100644
--- a/pkgs/development/python-modules/cvxopt/default.nix
+++ b/pkgs/development/python-modules/cvxopt/default.nix
@@ -14,7 +14,7 @@
 , withFftw ? true
 }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 buildPythonPackage rec {
   pname = "cvxopt";
diff --git a/pkgs/development/python-modules/numpy/default.nix b/pkgs/development/python-modules/numpy/default.nix
index 7009d1d1cd03..f3d8dcba31d3 100644
--- a/pkgs/development/python-modules/numpy/default.nix
+++ b/pkgs/development/python-modules/numpy/default.nix
@@ -12,7 +12,7 @@
 , setuptoolsBuildHook
  }:
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 let
   cfg = writeTextFile {
diff --git a/pkgs/tools/misc/hpl/default.nix b/pkgs/tools/misc/hpl/default.nix
index c131de021806..d688f3adf30e 100644
--- a/pkgs/tools/misc/hpl/default.nix
+++ b/pkgs/tools/misc/hpl/default.nix
@@ -1,6 +1,6 @@
 { stdenv, fetchurl, blas, lapack, mpi } :
 
-assert (!blas.is64bit) && (!lapack.is64bit);
+assert (!blas.isILP64) && (!lapack.isILP64);
 
 stdenv.mkDerivation rec {
   pname = "hpl";
diff --git a/pkgs/top-level/release-alternatives.nix b/pkgs/top-level/release-alternatives.nix
index eef239d4e0a8..7479377bd302 100644
--- a/pkgs/top-level/release-alternatives.nix
+++ b/pkgs/top-level/release-alternatives.nix
@@ -59,7 +59,7 @@ in
 {
   blas = mapListToAttrs supportedSystems (system': let system = lib.systems.elaborate { system = system'; };
     in mapListToAttrs (blasProviders system) (provider: let
-      is64bit = builtins.elem provider (["mkl64"] ++ lib.optional system.is64bit "openblas");
+      isILP64 = builtins.elem provider (["mkl64"] ++ lib.optional system.is64bit "openblas");
       pkgs = pkgsFun {
         config = { inherit allowUnfree; };
         system = system';
@@ -68,13 +68,13 @@ in
             lapackProvider = if provider == "mkl64"
                              then super.mkl
                              else builtins.getAttr provider super;
-            inherit is64bit;
+            inherit isILP64;
           };
           blas = super.blas.override {
             blasProvider = if provider == "mkl64"
                            then super.mkl
                            else builtins.getAttr provider super;
-            inherit is64bit;
+            inherit isILP64;
           };
         })];
       };