Add Makefile for auto-formatting

Makefile

@@ -0,0 +1,17 @@
+all: build/karg
+
+clean:
+	@rm -rf build
+
+fmt:
+	@clang-format -i $(shell find -not -path "./build/*" -name "*.[ch]")
+
+build:
+	@mkdir build
+	@cmake -B build -D CMAKE_TOOLCHAIN_FILE=$(CMAKE_TOOLCHAIN_FILE) \
+		-D LIBC_INCLUDE=$(LIBC_INCLUDE) -D LUA_INCLUDE=$(LUA_INCLUDE)
+
+FORCE:
+
+build/karg: FORCE | build
+	@cmake --build build