nix: Disable building profiled or dynamic libraries by default

We never need dynamic haskell libraries, because even the dynamic builds
only dynamically link non-haskell dependencies, but always link haskell
dependencies statically.

Profiled libraries are only required when running the memory test, so
explicitly enable them for the profiled package.

This also means, that we don't need to hide the memory test behind a
feature flag anymore. The reason always was assumed to be the big number
of rebuilds required for it. I assume ever since we moved off of
static-haskell-nix and back to nixpkgs-based builds, we have been
building profiled libraries for all our dependencies anway.

default.nix

@@ -55,8 +55,13 @@ let
     ];
 
   # Dynamic derivation for PostgREST
-  postgrest =
-    pkgs.haskell.packages."${compiler}".callCabal2nix name src { };
+  postgrest = pkgs.lib.pipe (pkgs.haskell.packages."${compiler}".callCabal2nix name src { }) [
+    # To allow ghc-datasize to be used.
+    lib.disableLibraryProfiling
+    # We are never going to use dynamic haskell libraries anyway. "Dynamic" refers to how
+    # non-haskell deps are linked. All haskell dependencies are always statically linked.
+    lib.disableSharedLibraries
+  ];
 
   staticHaskellPackage = import nix/static.nix { inherit compiler name pkgs src; };
 
@@ -64,15 +69,6 @@ let
   devCabalOptions =
     "-f dev --test-show-detail=direct";
 
-  profiledHaskellPackages =
-    pkgs.haskell.packages."${compiler}".extend (_: super:
-      {
-        mkDerivation =
-          args:
-          super.mkDerivation (args // { enableLibraryProfiling = true; });
-      }
-    );
-
   inherit (pkgs.haskell) lib;
 in
 rec {
@@ -85,12 +81,11 @@ rec {
     lib.dontCheck postgrest;
 
   # Profiled dynamic executable.
-  postgrestProfiled =
-    lib.enableExecutableProfiling (
-      lib.dontHaddock (
-        lib.dontCheck (profiledHaskellPackages.callCabal2nix name src { })
-      )
-    );
+  postgrestProfiled = pkgs.lib.pipe postgrestPackage [
+    lib.enableExecutableProfiling
+    lib.enableLibraryProfiling
+    lib.dontHaddock
+  ];
 
   inherit (postgrest) env;