Fix C template build error

[soxfox42]

Building the C template with recent (>=16) WASI SDKs caused the following error:

[wasm-validator error in function 1] unexpected false: Bulk memory operations require bulk memory [--enable-bulk-memory], on
(memory.fill
 (i32.const 100836)
 (i32.const 0)
 (i32.const 66)
)
[wasm-validator error in function 31] unexpected false: Bulk memory operations require bulk memory [--enable-bulk-memory], on
(memory.copy
 (local.get $0)
 (local.get $1)
 (local.get $2)
)
[wasm-validator error in function 32] unexpected false: Bulk memory operations require bulk memory [--enable-bulk-memory], on
(memory.fill
 (local.get $0)
 (local.get $1)
 (local.get $2)
)

This is due to WASI libc now using bulk memory operations. Building with --strip-all was removing the WebAssembly target features section, causing the validator to complain about bulk memory operations.