envdir-go: buildFlagsArray -> ldflags

pkgs/tools/misc/envdir-go/default.nix

@@ -14,10 +14,10 @@ buildGoPackage rec {
     sha256 = "1wdlblj127skgynf9amk7waabc3abbyxys9dvyc6c72zpcpdy5nc";
   };
 
-  preBuild = ''
-   # TODO: is there a way to get the commit ref so we can set main.buildCommit?
-    buildFlagsArray+=("-ldflags" "-X main.buildDate=1970-01-01T00:00:00+0000 -X main.buildVersion=${version}")
-'';
+  # TODO: is there a way to get the commit ref so we can set main.buildCommit?
+  ldflags = [
+    "-X main.buildDate=1970-01-01T00:00:00+0000" "-X main.buildVersion=${version}"
+  ];
 
   meta = {
     description = "A go rewrite of envdir";