more no_std compatibility

src/corpus/testcase.rs

@@ -169,7 +169,7 @@ where
     pub fn load_input(&mut self) -> Result<&I, AflError> {
         if self.input.is_none() {
             let input = I::from_file(self.filename.as_ref().ok_or(AflError::EmptyOptional(
-                "filename not specified".to_string(),
+                "filename not specified".into(),
             ))?)?;
             self.input = Some(input);
         }

src/engines/mod.rs

@@ -199,6 +199,7 @@ where
 
     fn fuzz_one(&mut self, state: &mut S) -> Result<usize, AflError> {
         let (testcase, idx) = state.corpus_mut().next()?;
+        #[cfg(feature = "std")] 
         println!("Cur entry: {}\tExecutions: {}", idx, state.executions());
         for stage in self.stages_mut() {
             stage.perform(testcase.clone(), state)?;

src/events/mod.rs

@@ -79,8 +79,9 @@ impl EventManager for LoggerEventManager {
         }
     }
 
-    fn fire<E: Event>(&mut self, event: E) -> Result<(), AflError> {
+    fn fire<E: Event>(&mut self, _event: E) -> Result<(), AflError> {
-        println!("{}", event);
+        #[cfg(feature = "std")] 
+        println!("{}", _event);
         Ok(())
     }
 

src/generators/mod.rs

@@ -1,10 +1,12 @@
+use alloc::rc::Rc;
+use alloc::vec::Vec;
+use core::cell::RefCell;
+use core::cmp::min;
+
 use crate::inputs::bytes::BytesInput;
 use crate::inputs::Input;
 use crate::utils::{HasRand, Rand};
 use crate::AflError;
-use alloc::rc::Rc;
-use core::cell::RefCell;
-use core::cmp::min;
 
 pub trait Generator<I>: HasRand
 where