refactor(tvix/nix-compat): support non-unicode Derivations

Derivations can have non-unicode strings in their env values, so the
ATerm representations are not necessarily String anymore, but Vec<u8>.

Change-Id: Ic23839471eb7f68d9c3c30667c878830946b6607
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8990
Tested-by: BuildkiteCI
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Autosubmit: flokli <flokli@flokli.de>

tvix/Cargo.lock

@@ -266,6 +266,17 @@ dependencies = [
  "byte-tools",
 ]
 
+[[package]]
+name = "bstr"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6798148dccfbff0fae41c7574d2fa8f1ef3492fba0face179de5d8d447d67b05"
+dependencies = [
+ "memchr",
+ "regex-automata",
+ "serde",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.12.1"
@@ -1346,6 +1357,7 @@ name = "nix-compat"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "bstr",
  "data-encoding",
  "glob",
  "serde",
@@ -1889,6 +1901,12 @@ dependencies = [
  "regex-syntax 0.7.1",
 ]
 
+[[package]]
+name = "regex-automata"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b7b6d6190b7594385f61bd3911cd1be99dfddcfc365a4160cc2ab5bff4aed294"
+
 [[package]]
 name = "regex-syntax"
 version = "0.6.29"