default to nightly build (#589)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

scripts/install-build-deps.sh

@@ -22,9 +22,13 @@ WABT_ZIP=
 
 unamestr=`uname`
 
+# Always install base toolchain first
 # toolchain with rust-src (for panic overrdides) and the right wasm32 toolchain
 rustup toolchain install $RUST_VER -c rust-src -t wasm32-unknown-unknown
-rustup default $RUST_VER
+
+echo "*** Installing nightly-$NIGHTLY_VER (sysroot build requires nightly)"
+rustup toolchain install nightly-$NIGHTLY_VER -c rust-src -t wasm32-unknown-unknown
+rustup default nightly-$NIGHTLY_VER
 
 if [ "$RUST_VER" != "stable" ]; then
   cargo install xargo

scripts/rust-version.sh

@@ -5,3 +5,5 @@
 
 RUST_VER=1.84
 # RUST_VER=stable
+
+NIGHTLY_VER=2024-11-22