Cannot build with feature 'debug'

[dwragge]

Hey there,

It appears that this commit broke the build script for the debug feature, it fails with

error[E0425]: cannot find value `is_wasm` in this scope
   --> /Users/dwragge/.cargo/registry/src/index.crates.io-6f17d22bba15001f/zstd-sys-2.0.10+zstd.1.5.6/build.rs:217:9

I guess it needs to be changed to need_wasm_shim.

Cheers