buildGoModule: fix cross-compilation with CGO_ENABLED=1

When building a go binary that's linking against some .so/.a, while
cross-compiling, we need to pass the correct compiler, otherwise
`go build` will fail with the not-so helpful error message:

```
gcc_arm64.S: Assembler messages:
gcc_arm64.S:28: Error: no such instruction: `stp x29,x30,[sp,'
gcc_arm64.S:32: Error: too many memory references for `mov'
gcc_arm64.S:34: Error: no such instruction: `stp x19,x20,[sp,'
gcc_arm64.S:37: Error: no such instruction: `stp x21,x22,[sp,'
gcc_arm64.S:40: Error: no such instruction: `stp x23,x24,[sp,'
gcc_arm64.S:43: Error: no such instruction: `stp x25,x26,[sp,'
gcc_arm64.S:46: Error: no such instruction: `stp x27,x28,[sp,'
gcc_arm64.S:50: Error: too many memory references for `mov'
gcc_arm64.S:51: Error: too many memory references for `mov'
gcc_arm64.S:52: Error: too many memory references for `mov'
gcc_arm64.S:54: Error: no such instruction: `blr x20'
gcc_arm64.S:55: Error: no such instruction: `blr x19'
gcc_arm64.S:57: Error: no such instruction: `ldp x27,x28,[sp,'
gcc_arm64.S:60: Error: no such instruction: `ldp x25,x26,[sp,'
gcc_arm64.S:63: Error: no such instruction: `ldp x23,x24,[sp,'
gcc_arm64.S:66: Error: no such instruction: `ldp x21,x22,[sp,'
gcc_arm64.S:69: Error: no such instruction: `ldp x19,x20,[sp,'
gcc_arm64.S:72: Error: no such instruction: `ldp x29,x30,[sp],'
```

pkgs/development/go-modules/generic/default.nix

@@ -46,7 +46,7 @@ with builtins;
 let
   args = removeAttrs args' [ "overrideModAttrs" "vendorSha256" "disabled" ];
 
-  go-modules = if vendorSha256 != null then go.stdenv.mkDerivation (let modArgs = {
+  go-modules = if vendorSha256 != null then stdenv.mkDerivation (let modArgs = {
 
     name = "${name}-go-modules";
 
@@ -119,7 +119,7 @@ let
       }
   ) // overrideModAttrs modArgs) else "";
 
-  package = go.stdenv.mkDerivation (args // {
+  package = stdenv.mkDerivation (args // {
     nativeBuildInputs = [ go ] ++ nativeBuildInputs;
 
     inherit (go) GOOS GOARCH;