fix: improve default handling

- no longer loads .env.example but explicitly sets default variables

Makefile

@@ -2,11 +2,14 @@ ifneq (,$(wildcard ./.env))
   include .env
   export
 else
-  $(warning .env file not found, loading defaults)
+  $(warning .env file not found, defaults will be used)
-  include .env.example
-  export
 endif
 
+# Default configuration
+FLAG_LEN ?= 32
+FLAG_FORMAT ?= ctf{FLAG_GOES_HERE}
+
+# Compilation variables
 RISCV_CC ?= riscv64-unknown-elf-gcc
 RISCV_ARCH_FLAGS ?= -march=rv32im -mabi=ilp32
 HOST_CC ?= gcc