remove scripts and run compilation directly in Containerfile.

Containerfile

@@ -7,12 +7,54 @@ RUN apt-get update \
   build-essential
 
 COPY submodules/libsecp256k1 /app
-COPY scripts/compile.sh /app
-COPY scripts/exported_functions /app
 
 WORKDIR /app
 
-RUN ./compile.sh
+# expose sha256 from libsecp256k1
+RUN sed -i 's/static \(void secp256k1_sha256_\(initialize\|write\|finalize\)\)/\1/' src/hash_impl.h
+RUN sed -i 's/static \(void secp256k1_sha256_\(initialize\|write\|finalize\)\)/extern \1/' src/hash.h
+
+# workaround for <https://github.com/emscripten-core/emscripten/issues/13551>
+RUN echo '{"type":"commonjs"}' > package.json
+
+# autogen
+RUN ./autogen.sh
+
+# configure
+RUN emconfigure ./configure \
+  --enable-module-schnorrsig=yes\
+  --enable-module-extrakeys=yes \
+  --with-ecmult-window=4 \
+  --with-ecmult-gen-precision=2 \
+  --disable-shared \
+  CFLAGS="-fdata-sections -ffunction-sections -O2" \
+  LDFLAGS="-Wl,--gc-sections"
+
+# make
+RUN emmake make FORMAT=wasm
+RUN emmake make src/precompute_ecmult-precompute_ecmult FORMAT=wasm
+
+# reset output dir
+RUN rm -rf out
+RUN mkdir -p out
+
+# compile
+RUN emcc src/precompute_ecmult-precompute_ecmult.o \
+  src/libsecp256k1_precomputed_la-precomputed_ecmult.o \
+  src/libsecp256k1_precomputed_la-precomputed_ecmult_gen.o \
+  src/libsecp256k1_la-secp256k1.o \
+  -O3 \
+  -s WASM=1 \
+  -s TOTAL_MEMORY=1mb \
+  -s "BINARYEN_METHOD='native-wasm'" \
+  -s DETERMINISTIC=1 \
+  -s EXPORTED_FUNCTIONS="_malloc _free _secp256k1_context_create _secp256k1_keypair_create _secp256k1_keypair_xonly_pub _secp256k1_xonly_pubkey_parse _secp256k1_xonly_pubkey_serialize _secp256k1_schnorrsig_sign32 _secp256k1_schnorrsig_verify _secp256k1_sha256_initialize _secp256k1_sha256_write _secp256k1_sha256_finalize" \
+  -s MINIMAL_RUNTIME=1 \
+  -s NO_EXIT_RUNTIME=1 \
+  -o out/secp256k1.js
+
+# verify
+RUN ls -la out/
 
 # copy outputs to mounted volume
 CMD ["cp", "-r", "/app/out", "/out"]