Merge pull request #1194 from IntersectMBO/js/without-nix

Add script for preparing the wasm libraries for building without Nix

Author: palas

.changes/20260706_cardano_wasm_wasm_libs_without_nix_script.yml

@@ -0,0 +1,7 @@
+project: cardano-wasm
+pr: 1194
+kind:
+  - maintenance
+description: |
+  Add `scripts/wasm-without-nix/build-wasm-libs.sh` for building the wasm32-wasi
+  C library dependencies (libsodium, libsecp256k1, libblst) without Nix

cardano-wasm/README.md

@@ -13,9 +13,11 @@ Enter the Nix shell by writing `nix develop .#wasm` on a shell in this folder an
 For the installation we will need some dependencies. In Debian based distros we can install them using apt like this:
 
 ```bash
-sudo apt install happy pkgconf libtool git wget curl jq unzip zstd tar gzip
+sudo apt install happy pkgconf libtool make automake autoconf file git wget curl jq unzip zstd tar gzip
 ```
 
+(`jq`, `unzip`, `zstd`, `wget` and `curl` are needed by ghc-wasm-meta's installer rather than by the build itself, and `happy` is needed by some Haskell dependencies during the build.)
+
 #### Installing `ghc` for wasm
 
 Then it is necessary to get `ghc` for wasm, and you see how to do that [here](https://gitlab.haskell.org/haskell-wasm/ghc-wasm-meta#getting-started-without-nix). At the moment, it is necessary to install a version of `ghc` that has `base <= 4.20`, so I would recommend installing `wasm32-wasi-9.10` like this:
@@ -40,8 +42,18 @@ And that should not return:
 wasm32-wasi-ghc: command not found
 ```
 
+If the reported version is not 9.10.x, double-check the `FLAVOUR` used above before continuing: with a different `base` version the build will only fail much later, with confusing dependency resolution errors.
+
 Then we need to compile three libraries to WASM: `libblst`, `libsodium`, and `libsecp256k1`.
 
+The script [`scripts/wasm-without-nix/build-wasm-libs.sh`](../scripts/wasm-without-nix/build-wasm-libs.sh) automates all the steps in this section: it builds the same pinned versions of the libraries as the Nix build, installs them into a prefix of your choice, verifies the results are really wasm, and generates a `cabal.project` fragment that points the build at them. From the root of this repository run:
+
+```bash
+PREFIX=wasm-libs SRC_ROOT=wasm-libs-src ./scripts/wasm-without-nix/build-wasm-libs.sh
+```
+
+and then follow the instructions it prints at the end (in particular, exporting `PKG_CONFIG_PATH`). In that case you can skip straight to the [Compiling `cardano-wasm` section](#compiling-cardano-wasm). The rest of this section explains the equivalent manual steps.
+
 In order to not interfere with the system library installation, we will create a folder to serve as our prefix:
 
 ```bash