Fix callPackage still producing dynamic executables

[FPtje]

This was due to staticHaskellBinariesOverlay overlay changing every existing package to build statically, but not every new package called with callPackage.

Here's an example building against my own glualint:

Before

cd survey
nix repl --file default.nix --print-build-logs
nix-repl> :b (haskellPackages.extend (normalPkgs.callPackage /home/falco/Programs/glualint/nix/haskell-overlay.nix {})).callPackage /home/falco/Programs/glualint/default.nix {
}
This derivation produced the following outputs:
  out -> /nix/store/5qfjn4xkw1wwybywjq5qxr1dhsd16kw0-glualint-0.1.0.0
file /nix/store/5qfjn4xkw1wwybywjq5qxr1dhsd16kw0-glualint-0.1.0.0/bin/glualint
/nix/store/5qfjn4xkw1wwybywjq5qxr1dhsd16kw0-glualint-0.1.0.0/bin/glualint: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /nix/store/134sxj760d4nx8g85scj0h41bf8p7b7j-musl-1.2.3/lib/ld-musl-x86_64.so.1, stripped

After

nix-repl> :b (haskellPackages.extend (normalPkgs.callPackage /home/falco/Programs/glualint/nix/haskell-overlay.nix {})).callPackage /home/falco/Programs/glualint/default.nix {}

This derivation produced the following outputs:
  out -> /nix/store/24dbxj94lisb3hmcwjs3vkk8w4xlhsar-glualint-0.1.0.0

file /nix/store/24dbxj94lisb3hmcwjs3vkk8w4xlhsar-glualint-0.1.0.0/bin/glualint
/nix/store/24dbxj94lisb3hmcwjs3vkk8w4xlhsar-glualint-0.1.0.0/bin/glualint: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, stripped

[FPtje]

I was hoping I could get rid of this map, as the callPackage override would take over its functionality. That doesn't appear to happen, though, and leaving this out will cause any regular executables to be dynamically linked.