[c/c++] minimal cc/ld wrapper instead of LD_LIBRARY_PATH

[Mic92]

LD_LIBRARY_PATH breaks users' executable in the following ways:

• Executables not part of devshell might pick up libraries from LD_LIBRARY_PATH, this can lead to incompatible libraries being loaded and crash executables. This is very likely to happen on NixOS with different release channels or on Non-NixOS distributions
• Executables compiled in devshell won't run if the environment is unset or users tries to start them outside of devshell

Instead a minimal cc/ld wrapper could set an rpath and interpreter:

#!/usr/bin/env bash
exec /nix/store/xxxxx-gcc-unwrapped/bin/gcc -Wl,-rpath=$DEVSHELL_ROOT/lib" -Wl,-dynamic-linker=$NIX_DYNAMIC_LINKER "$@"

#!/usr/bin/env bash
exec /nix/store/xxxxx-binutils-unwrapped/bin/ld -rpath "$DEVSHELL_ROOT/lib" -dynamic-linker "$NIX_DYNAMIC_LINKER" "$@"

Dynamic linker can be obtained from the wrapped version at build time: $(cat $NIX_CC/nix-support/dynamic-linker)

[Mic92]

Also related to #102