Switch to Amazon Linux 2 Lambda runtime

Makefile

@@ -33,13 +33,21 @@ lint:
 test:
 	go test -v -cover ./...
 
+# https://github.com/messense/homebrew-macos-cross-toolchains
+TARGET := x86_64-unknown-linux-gnu
+export CC_x86_64_unknown_linux_gnu  = $(TARGET)-gcc
+export CXX_x86_64_unknown_linux_gnu = $(TARGET)-g++
+export AR_x86_64_unknown_linux_gnu  = $(TARGET)-ar
+export CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER = $(TARGET)-gcc
+export RUSTFLAGS = -C link-arg=-s
+
 RUST_FUNCS := $(subst /,,$(dir $(wildcard */lambda.rs)))
 
 rust_funcs := $(RUST_FUNCS:%=rust-%)
 
 rust: $(rust_funcs)
 
 $(rust_funcs):
-	RUSTFLAGS="-C link-arg=-s" cargo build --release --target x86_64-unknown-linux-musl --bin $(@:rust-%=%)
+	cargo build --release --target $(TARGET) --bin $(@:rust-%=%)
 	mkdir -p bin/$(@:rust-%=%)
-	cp -f target/x86_64-unknown-linux-musl/release/$(@:rust-%=%) bin/$(@:rust-%=%)/bootstrap
+	cp -f target/$(TARGET)/release/$(@:rust-%=%) bin/$(@:rust-%=%)/bootstrap

index.ts

@@ -62,7 +62,7 @@ export class DilbertFeedStack extends cdk.Stack {
       functionName: `${id}-heartbeat`,
       code: lambda.Code.fromAsset('bin/heartbeat'),
       handler: 'bootstrap',
-      runtime: lambda.Runtime.PROVIDED,
+      runtime: lambda.Runtime.PROVIDED_AL2,
       memorySize: 128,
       timeout: cdk.Duration.seconds(10),
       logRetention: logs.RetentionDays.ONE_MONTH,