nailing-cargo: Provide a dummy build.rs

Without this, cargo might do this:

    package `<crate> <version> (/home/....)` specifies that it links
    to `<some library>` but does not have a custom build script

When generating a lockfile it doesn't actually need to look at the
build.rs so an empty one will do fine to placate it.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/nailing-cargo b/nailing-cargo
index d6f0a5bd075fbc8868daad01946b87b8a85a77f3..4cc9eac3314c9087698cea39b6eaf2df3a2d9f4c 100755 (executable)
--- a/nailing-cargo
+++ b/nailing-cargo
@@ -547,10 +547,10 @@ ENDLK
 ENDCP
     $pre .= <<'ENDPRE';
         shift;
-        mkdir -p src; >src/lib.rs;
+        mkdir -p src; >src/lib.rs; >build.rs
 ENDPRE
     $post = <<'ENDPOST';
-        rm -r src Cargo.toml;
+        rm -r src Cargo.toml build.rs;
 ENDPOST
   }
   my $addpath = (cfg_uc qw(oot path_add)) //