Prepare for portable build process

src/arch/8051/arch.mk

@@ -0,0 +1,25 @@
+CC=sdcc -mmcs51
+OBJ=$(patsubst src/%.c,$(BUILD)/%.rel,$(SRC))
+
+# Run EC rom in simulator
+sim: $(BUILD)/ec.rom
+	cargo run \
+		--release \
+		--manifest-path ecsim/Cargo.toml \
+		--no-default-features \
+		-- $<
+
+# Convert from Intel Hex format to binary
+$(BUILD)/ec.rom: $(BUILD)/ec.ihx
+	@mkdir -p $(@D)
+	makebin -p < $< > $@
+
+# Link object files into Intel Hex format
+$(BUILD)/ec.ihx: $(OBJ)
+	@mkdir -p $(@D)
+	$(CC) -o $@ $^
+
+# Compile C files into object files
+$(BUILD)/%.rel: src/%.c $(INCLUDE)
+	@mkdir -p $(@D)
+	$(CC) -o $@ -c $<