Ensure mkdir doesn't fail if dist exists

compile

@@ -76,7 +76,7 @@ if [[ $BUILD_TYPE == "debug" ]]; then
 	PCKR_OUT="pckr"
 	PAKRD_OUT="libpakrd.a"
 else
-	mkdir dist
+	mkdir -p dist
 	cp ./include/pak.h dist
 	CFLAGS+="-O3 "
 	PCKR_OUT="dist/pckr"

src/pak.c

@@ -229,7 +229,9 @@ void close_asset_pack(asset_pack_t **pack) {
     free((*pack)->toc);
   }
 
+  if ((*pack)->fp) {
     fclose((*pack)->fp);
+  }
 
   free(*pack);