f check for clang wasm32 as well as rustc

Author: TheBlueMatt

genbindings.sh

@@ -180,8 +180,14 @@ else
 fi
 
 if [ "$(rustc --print target-list | grep wasm32-wasi)" != "" ]; then
-	cargo rustc -v --target=wasm32-wasi -- -C embed-bitcode=yes
-	CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release --target=wasm32-wasi -- -C opt-level=s -C linker-plugin-lto -C lto
+	# Test to see if clang supports wasm32 as a target (which is needed to build rust-secp256k1)
+	echo "int main() {}" > genbindings_wasm_test_file.c
+	clang -nostdlib -o /dev/null --target=wasm32-wasi -Wl,--no-entry genbindings_wasm_test_file.c > /dev/null 2>&1 &&
+	# And if it does, build a WASM binary without capturing errors
+	cargo rustc -v --target=wasm32-wasi -- -C embed-bitcode=yes &&
+	CARGO_PROFILE_RELEASE_LTO=true cargo rustc -v --release --target=wasm32-wasi -- -C opt-level=s -C linker-plugin-lto -C lto ||
+	echo "Cannot build WASM lib as clang does not seem to support the wasm32-wasi target"
+	rm genbindings_wasm_test_file.c
 fi
 
 # Now build with LTO on on both C++ and rust, but without cross-language LTO: