build(core): remove LD_LIBRARY_PATH workaround from Makefile

Normal CI workflows seem to work fine with it and it broke
`make upload` on some setups.

[no changelog]

Author: mmilata

core/Makefile

@@ -150,9 +150,6 @@ endif
 
 SCONS = scons $(SCONS_OPTS) $(SCONS_VARS)
 
-# LD_LIBRARY_PATH workaround: https://discourse.nixos.org/t/nixpkgs-nixos-unstable-many-package-fail-with-glibc-2-38-not-found/35078 https://github.com/NixOS/nixpkgs/issues/287764
-unexport LD_LIBRARY_PATH
-
 ## help commands:
 
 help: ## show this help