fix: major bug in allocator

makefile

@@ -1,5 +1,5 @@
 RELEASE_flags=-DNDEBUG -O2 -g0
-DEBUG_flags=-std=c23 -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Wvla -g -Og
+DEBUG_flags=-std=c23 -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Wvla -g -O0
 
 clean:
 	rm -fr bin

niarena.h

@@ -81,8 +81,9 @@ niarena_alloc(NIArena **self, size_t size)
 		niarena_error("niarena_alloc: out of memory inside of the arena");
 		return NULL;
 	}
+	void *ret = (void *)(((char *)arena->buffer) + arena->offset);
 	arena->offset += size;
-	return (void *)((char *)arena->buffer + arena->offset);
+	return ret;
 }
 
 void