Enable Wall/Wextra flags for Wasm builds

We only had one warning in Wasm stubs which this change fixes as well.

Makefile

@@ -44,6 +44,7 @@ WASMCC?=$(WASI_SDK)/bin/clang++
 WASIROOT?=$(WASI_SDK)/share/wasi-sysroot
 
 WASM_FLAGS=--target=wasm32-wasi --sysroot=$(WASIROOT)
+WASM_FLAGS+=-Wall -Wextra
 WASM_FLAGS+=-O3 -DNDEBUG -nostartfiles -nostdlib -Wl,--no-entry -Wl,-s
 WASM_FLAGS+=-mcpu=mvp # make sure clang doesn't use post-MVP features like sign extension
 WASM_FLAGS+=-fno-slp-vectorize -fno-vectorize -fno-unroll-loops

tools/wasmstubs.cpp

@@ -20,7 +20,7 @@ extern "C" void* sbrk(intptr_t increment)
 
 	size_t heap_size = __builtin_wasm_memory_size(0) * WASM_PAGE_SIZE;
 
-	if (sbrkp > heap_size)
+	if (size_t(sbrkp) > heap_size)
 	{
 		size_t diff = (sbrkp - heap_size + WASM_PAGE_SIZE - 1) / WASM_PAGE_SIZE;