treewide: use blas and lapack

This makes packages use lapack and blas, which can wrap different
BLAS/LAPACK implementations.

treewide: cleanup from blas/lapack changes

A few issues in the original treewide:

- can’t assume blas64 is a bool
- unused commented code

pkgs/servers/mail/rspamd/default.nix

@@ -1,6 +1,6 @@
 { stdenv, lib, fetchFromGitHub, cmake, perl
 , glib, luajit, openssl, pcre, pkgconfig, sqlite, ragel, icu
-, hyperscan, jemalloc, openblas, lua, libsodium
+, hyperscan, jemalloc, blas, lapack, lua, libsodium
 , withBlas ? true
 , withHyperscan ? stdenv.isx86_64
 , withLuaJIT ? stdenv.isx86_64
@@ -22,7 +22,7 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ cmake pkgconfig perl ];
   buildInputs = [ glib openssl pcre sqlite ragel icu jemalloc libsodium ]
     ++ lib.optional withHyperscan hyperscan
-    ++ lib.optional withBlas openblas
+    ++ lib.optionals withBlas [ blas lapack ]
     ++ lib.optional withLuaJIT luajit ++ lib.optional (!withLuaJIT) lua;
 
   cmakeFlags = [