diff --git a/doc/using/overlays.xml b/doc/using/overlays.xml
index 5f808839dd0..3fa68e32a3c 100644
--- a/doc/using/overlays.xml
+++ b/doc/using/overlays.xml
@@ -140,8 +140,8 @@ self: super:
  <section xml:id="sec-overlays-alternatives">
    <title>Using overlays to configure alternatives</title>
    <para>
-     Certain software has different implementations of the same
-     interface. Other distributions have functionality to switch
+     Certain software packages have different implementations of the
+     same interface. Other distributions have functionality to switch
      between these. For example, Debian provides <link
      xlink:href="https://wiki.debian.org/DebianAlternatives">DebianAlternatives</link>.
      Nixpkgs has what we call <literal>alternatives</literal>, which
@@ -160,8 +160,9 @@ self: super:
          </para>
          <para>
            The Nixpkgs attribute is <literal>openblas</literal> for
-           ILP64 and <literal>openblasCompat</literal> for LP64. This
-           is the default.
+           ILP64 (integer width = 64 bits) and
+           <literal>openblasCompat</literal> for LP64 (integer width =
+           32 bits). <literal>openblasCompat</literal> is the default.
          </para>
        </listitem>
        <listitem>
@@ -190,8 +191,15 @@ self: super:
        #83888</link>, we are able to override the ‘blas’ and ‘lapack’
        packages to use different implementations, through the
        ‘blasProvider’ and ‘lapackProvider’ argument. This can be used
-       to select a different provider. For example, an overlay can be
-       created that looks like:
+       to select a different provider. BLAS providers will have
+       symlinks in <literal>$out/lib/libblas.so.3</literal> and
+       <literal>$out/lib/libcblas.so.3</literal> to their respective
+       BLAS libraries. Likewise, LAPACK providers will have symlinks
+       in <literal>$out/lib/liblapack.so.3</literal> and
+       <literal>$out/lib/liblapacke.so.3</literal> to their respective
+       LAPCK libraries. For example, Intel MKL is both a BLAS and
+       LAPACK provider. An overlay can be created to use Intel MKL
+       that looks like:
      </para>
      <programlisting>
 self: super:
@@ -208,9 +216,12 @@ self: super:
      <para>
        This overlay uses Intel’s MKL library for both BLAS and LAPACK
        interfaces. Note that the same can be accomplished at runtime
-       using <literal>LD_PRELOAD</literal> of libblas.so.3 and
-       liblapack.so.3.
+       using <literal>LD_LIBRARY_PATH</literal> of libblas.so.3 and
+       liblapack.so.3. For instance:
      </para>
+     <programlisting>
+$ LD_LIBRARY_PATH=$(nix-build -A mkl)/lib:$LD_LIBRARY_PATH nix-shell -p octave --run octave
+     </programlisting>
      <para>
        Intel MKL requires an <literal>openmp</literal> implementation
        when running with multiple processors. By default,
@@ -221,8 +232,8 @@ self: super:
        set it with <literal>LD_PRELOAD</literal>. Note that
        <literal>mkl</literal> is only available on
        <literal>x86_64-linux</literal> and
-       <literal>x86_64-darwin</literal>. Moreover, Hydra is not build
-       and distributing pre-compiled binaries using it.
+       <literal>x86_64-darwin</literal>. Moreover, Hydra is not
+       building and distributing pre-compiled binaries using it.
      </para>
      <para>
        For BLAS/LAPACK switching to work correctly, all packages must
diff --git a/pkgs/build-support/alternatives/blas/default.nix b/pkgs/build-support/alternatives/blas/default.nix
index 8bba49b4550..bdee6688a74 100644
--- a/pkgs/build-support/alternatives/blas/default.nix
+++ b/pkgs/build-support/alternatives/blas/default.nix
@@ -63,7 +63,7 @@ stdenv.mkDerivation {
   installPhase = (''
   mkdir -p $out/lib $dev/include $dev/lib/pkgconfig
 
-  libblas="${lib.getLib blasProvider}/lib/libblas${stdenv.hostPlatform.extensions.sharedLibrary}"
+  libblas="${lib.getLib blasProvider}/lib/libblas${canonicalExtension}"
 
   if ! [ -e "$libblas" ]; then
     echo "$libblas does not exist, ${blasProvider.name} does not provide libblas."
@@ -100,7 +100,7 @@ Libs: -L$out/lib -lblas
 Cflags: -I$dev/include
 EOF
 
-  libcblas="${lib.getLib blasProvider}/lib/libcblas${stdenv.hostPlatform.extensions.sharedLibrary}"
+  libcblas="${lib.getLib blasProvider}/lib/libcblas${canonicalExtension}"
 
   if ! [ -e "$libcblas" ]; then
     echo "$libcblas does not exist, ${blasProvider.name} does not provide libcblas."
diff --git a/pkgs/build-support/alternatives/lapack/default.nix b/pkgs/build-support/alternatives/lapack/default.nix
index e260ad1bd93..5a19916f83e 100644
--- a/pkgs/build-support/alternatives/lapack/default.nix
+++ b/pkgs/build-support/alternatives/lapack/default.nix
@@ -41,7 +41,7 @@ stdenv.mkDerivation {
   installPhase = (''
   mkdir -p $out/lib $dev/include $dev/lib/pkgconfig
 
-  liblapack="${lib.getLib lapackProvider}/lib/liblapack${stdenv.hostPlatform.extensions.sharedLibrary}"
+  liblapack="${lib.getLib lapackProvider}/lib/liblapack${canonicalExtension}"
 
   if ! [ -e "$liblapack" ]; then
     echo "$liblapack does not exist, ${lapackProvider.name} does not provide liblapack."
@@ -74,7 +74,7 @@ Cflags: -I$dev/include
 Libs: -L$out/lib -llapack
 EOF
 
-  liblapacke="${lib.getLib lapackProvider}/lib/liblapacke${stdenv.hostPlatform.extensions.sharedLibrary}"
+  liblapacke="${lib.getLib lapackProvider}/lib/liblapacke${canonicalExtension}"
 
   if ! [ -e "$liblapacke" ]; then
     echo "$liblapacke does not exist, ${lapackProvider.name} does not provide liblapacke."
diff --git a/pkgs/development/libraries/science/math/mkl/default.nix b/pkgs/development/libraries/science/math/mkl/default.nix
index f9026ec7b99..ee861c14ab4 100644
--- a/pkgs/development/libraries/science/math/mkl/default.nix
+++ b/pkgs/development/libraries/science/math/mkl/default.nix
@@ -114,10 +114,10 @@ in stdenvNoCC.mkDerivation {
     '') + ''
 
     # Setup symlinks for blas / lapack
-    ln -s $out/lib/libmkl_rt${stdenvNoCC.hostPlatform.extensions.sharedLibrary} $out/lib/libblas${stdenvNoCC.hostPlatform.extensions.sharedLibrary}
-    ln -s $out/lib/libmkl_rt${stdenvNoCC.hostPlatform.extensions.sharedLibrary} $out/lib/libcblas${stdenvNoCC.hostPlatform.extensions.sharedLibrary}
-    ln -s $out/lib/libmkl_rt${stdenvNoCC.hostPlatform.extensions.sharedLibrary} $out/lib/liblapack${stdenvNoCC.hostPlatform.extensions.sharedLibrary}
-    ln -s $out/lib/libmkl_rt${stdenvNoCC.hostPlatform.extensions.sharedLibrary} $out/lib/liblapacke${stdenvNoCC.hostPlatform.extensions.sharedLibrary}
+    ln -s $out/lib/libmkl_rt${stdenvNoCC.hostPlatform.extensions.sharedLibrary} $out/lib/libblas${stdenvNoCC.hostPlatform.extensions.sharedLibrary}${stdenvNoCC.lib.optionalString stdenvNoCC.hostPlatform.isLinux ".3"}
+    ln -s $out/lib/libmkl_rt${stdenvNoCC.hostPlatform.extensions.sharedLibrary} $out/lib/libcblas${stdenvNoCC.hostPlatform.extensions.sharedLibrary}${stdenvNoCC.lib.optionalString stdenvNoCC.hostPlatform.isLinux ".3"}
+    ln -s $out/lib/libmkl_rt${stdenvNoCC.hostPlatform.extensions.sharedLibrary} $out/lib/liblapack${stdenvNoCC.hostPlatform.extensions.sharedLibrary}${stdenvNoCC.lib.optionalString stdenvNoCC.hostPlatform.isLinux ".3"}
+    ln -s $out/lib/libmkl_rt${stdenvNoCC.hostPlatform.extensions.sharedLibrary} $out/lib/liblapacke${stdenvNoCC.hostPlatform.extensions.sharedLibrary}${stdenvNoCC.lib.optionalString stdenvNoCC.hostPlatform.isLinux ".3"}
   '';
 
   # fixDarwinDylibName fails for libmkl_cdft_core.dylib because the
diff --git a/pkgs/development/libraries/science/math/openblas/default.nix b/pkgs/development/libraries/science/math/openblas/default.nix
index c55a5cb7878..f6a40204587 100644
--- a/pkgs/development/libraries/science/math/openblas/default.nix
+++ b/pkgs/development/libraries/science/math/openblas/default.nix
@@ -178,10 +178,10 @@ EOF
     done
 
     # Setup symlinks for blas / lapack
-    ln -s $out/lib/libopenblas${stdenv.hostPlatform.extensions.sharedLibrary} $out/lib/libblas${stdenv.hostPlatform.extensions.sharedLibrary}
-    ln -s $out/lib/libopenblas${stdenv.hostPlatform.extensions.sharedLibrary} $out/lib/libcblas${stdenv.hostPlatform.extensions.sharedLibrary}
-    ln -s $out/lib/libopenblas${stdenv.hostPlatform.extensions.sharedLibrary} $out/lib/liblapack${stdenv.hostPlatform.extensions.sharedLibrary}
-    ln -s $out/lib/libopenblas${stdenv.hostPlatform.extensions.sharedLibrary} $out/lib/liblapacke${stdenv.hostPlatform.extensions.sharedLibrary}
+    ln -s $out/lib/libopenblas${stdenv.hostPlatform.extensions.sharedLibrary} $out/lib/libblas${stdenv.hostPlatform.extensions.sharedLibrary}${stdenv.lib.optionalString stdenv.hostPlatform.isLinux ".3"}
+    ln -s $out/lib/libopenblas${stdenv.hostPlatform.extensions.sharedLibrary} $out/lib/libcblas${stdenv.hostPlatform.extensions.sharedLibrary}${stdenv.lib.optionalString stdenv.hostPlatform.isLinux ".3"}
+    ln -s $out/lib/libopenblas${stdenv.hostPlatform.extensions.sharedLibrary} $out/lib/liblapack${stdenv.hostPlatform.extensions.sharedLibrary}${stdenv.lib.optionalString stdenv.hostPlatform.isLinux ".3"}
+    ln -s $out/lib/libopenblas${stdenv.hostPlatform.extensions.sharedLibrary} $out/lib/liblapacke${stdenv.hostPlatform.extensions.sharedLibrary}${stdenv.lib.optionalString stdenv.hostPlatform.isLinux ".3"}
   '';
 
   meta = with stdenv.lib; {
diff --git a/pkgs/development/python-modules/scipy/default.nix b/pkgs/development/python-modules/scipy/default.nix
index a9947e7e689..ace6c248ab2 100644
--- a/pkgs/development/python-modules/scipy/default.nix
+++ b/pkgs/development/python-modules/scipy/default.nix
@@ -53,6 +53,8 @@ in buildPythonPackage rec {
 
   setupPyBuildFlags = [ "--fcompiler='gnu95'" ];
 
+  SCIPY_USE_G77_ABI_WRAPPER = 1;
+
   meta = {
     description = "SciPy (pronounced 'Sigh Pie') is open-source software for mathematics, science, and engineering. ";
     homepage = "https://www.scipy.org/";