add basic Dockerfile

Dockerfile

@@ -0,0 +1,36 @@
+FROM debian:buster
+
+RUN apt update && \
+  # Install common dependencies
+  apt install -y \
+    cmake \
+    curl \
+    g++ \
+    gcc \
+    git \
+    gnupg \
+    lsb-release \
+    make \
+    software-properties-common \
+    wget && \
+  # Install LLVM:12
+  curl -sSf https://apt.llvm.org/llvm.sh | bash -s -- 12 && \
+  # Install Node.js:14
+  curl -fsSL https://deb.nodesource.com/setup_14.x | bash - && \
+  apt install nodejs -y && \
+  # Install Rust nightly
+  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | bash -s -- -y \
+    --default-toolchain nightly \
+    --profile minimal \
+    --component clippy,rustfmt,rust-src \
+    --target wasm32-unknown-unknown && \
+  echo 'source $HOME/.cargo/env' >> $HOME/.bashrc && \
+  # Install wasm-opt from binaryen
+  git clone --depth 1 --branch version_100 https://github.com/WebAssembly/binaryen.git /binaryen && \
+  cd /binaryen && \
+  cmake . && \
+  make -j$(nproc) && \
+  make install && \
+  rm -rf /binaryen && \
+  # Remove apt files
+  rm -rf /var/lib/{apt,dpkg,cache,log}/

Makefile

@@ -6,7 +6,7 @@ build-js:
 build-node-%: export PAIR = $(subst +, ,$(subst build-node-,,$@))
 build-node-%:
 	cargo build --package secp256k1-node --target $(firstword $(PAIR)) -Z build-std=panic_abort,std --release
-	cp -f target/$(firstword $(PAIR))/release/libsecp256k1_node.so lib/secp256k1-$(lastword $(PAIR)).so
+	mkdir -p lib && cp -f target/$(firstword $(PAIR))/release/libsecp256k1_node.so lib/secp256k1-$(lastword $(PAIR)).so
 	strip lib/secp256k1-$(lastword $(PAIR)).so
 
 .PHONY: build-node-debug
@@ -17,7 +17,7 @@ build-node-debug:
 build-node-debug-%: export PAIR = $(subst +, ,$(subst build-node-debug-,,$@))
 build-node-debug-%:
 	cargo build --package secp256k1-node --target $(firstword $(PAIR))
-	cp -f target/$(firstword $(PAIR))/debug/libsecp256k1_node.so lib/secp256k1-$(lastword $(PAIR)).so
+	mkdir -p lib && cp -f target/$(firstword $(PAIR))/debug/libsecp256k1_node.so lib/secp256k1-$(lastword $(PAIR)).so
 
 .PHONY: build-wasm
 build-wasm: