Fixed libafl_atheris Makefile and flag read (#1499)

Author: eceo902

fuzzers/libafl_atheris/Makefile

@@ -32,7 +32,7 @@ fuzzer: target/release/libafl_atheris.a atheris env
 	)
 
 clean:
-	rm env
+	rm -rf env
 
 env:
 	python3 -m venv env

fuzzers/libafl_atheris/src/lib.rs

@@ -170,7 +170,7 @@ pub extern "C" fn LLVMFuzzerRunDriver(
         .get_one::<String>("remote_broker_addr")
         .map(|s| s.parse().expect("Invalid broker address"));
     let input_dirs: Vec<PathBuf> = matches
-        .get_many::<PathBuf>("input")
+        .get_many::<String>("input")
         .map(|v| v.map(PathBuf::from).collect())
         .unwrap_or_default();
     let output_dir = matches