Remove build scripts during dummyfication

Otherwise builds fail with an error like:

Compiling simple-dep v0.1.0 (/private/var/folders/5h/b11m6fxj2tqgbxwz5bgjy42c0000gn/T/nix-build-some-name.drv-0/dummy-src)
error: couldn't read build.rs: No such file or directory (os error 2)

lib.nix

@@ -91,9 +91,13 @@ rec
         config = writeText "config" cargoconfig;
         cargolock' = builtinz.writeTOML "Cargo.toml" cargolock;
         fixupCargoToml = cargotoml:
-          # Since we pretend everything is a lib, we remove any mentions of
-          # binaries
-          removeAttrs cargotoml ["bin" "example" "lib" "test" "bench" ];
+          let attrs =
+                # Since we pretend everything is a lib, we remove any mentions
+                # of binaries
+                removeAttrs cargotoml [ "bin" "example" "lib" "test" "bench" ];
+          in attrs // lib.optionalAttrs (lib.hasAttr "package" attrs) {
+                        package = removeAttrs attrs.package [ "build" ];
+                      };
         cargotomlss = writeText "foo"
           (lib.concatStrings (lib.mapAttrsToList
             (k: v: "${k}\n${builtinz.writeTOML "Cargo.toml-ds-aa" (fixupCargoToml v)}\n")

test.nix

@@ -80,10 +80,10 @@ rec
     (pkgs.lib.cleanSource ./test/simple-dep)
     {};
 
-  binary = naersk.buildPackage
-    (pkgs.lib.cleanSource ./test/binary)
+  dummyfication = naersk.buildPackage
+    (pkgs.lib.cleanSource ./test/dummyfication)
     {};
-  binary_test = pkgs.runCommand "binary-test" { buildInputs = [ binary ]; }
+  dummyfication_test = pkgs.runCommand "dummyfication-test" { buildInputs = [ dummyfication ]; }
     "my-bin > $out";
 
   workspace = naersk.buildPackage

test/dummyfication/Cargo.lock

@@ -1,3 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
 [[package]]
 name = "aho-corasick"
 version = "0.7.6"
@@ -6,14 +8,6 @@ dependencies = [
  "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "binary"
-version = "0.1.0"
-dependencies = [
- "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "c2-chacha"
 version = "0.2.2"
@@ -28,6 +22,14 @@ name = "cfg-if"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "dummyfication"
+version = "0.1.0"
+dependencies = [
+ "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.1.12"

test/dummyfication/Cargo.toml

@@ -1,8 +1,9 @@
 [package]
-name = "binary"
+name = "dummyfication"
 version = "0.1.0"
 authors = ["nicolas <nicolas@nmattia.com>"]
 edition = "2018"
+build = "build.rs"
 
 [dependencies]
 rand = "0.7.0"

test/dummyfication/build.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Running a custom build...");
+}