fix up core build with alloc

core/src/ctxt.rs

@@ -257,6 +257,7 @@ mod internal {
 #[cfg(feature = "alloc")]
 mod alloc_support {
     use core::any::Any;
+    use alloc::boxed::Box;
 
     use crate::props::ErasedProps;
 

core/src/lib.rs

@@ -11,7 +11,10 @@ If you're looking to use `emit` in an application you can use this library direc
 */
 
 #![deny(missing_docs)]
-#![cfg_attr(not(any(test, feature = "std")), no_std)]
+#![cfg_attr(not(test), no_std)]
+
+#[cfg(feature = "std")]
+extern crate std;
 
 #[cfg(feature = "alloc")]
 extern crate alloc;

core/src/path.rs

@@ -242,7 +242,7 @@ impl<'a> serde::Serialize for Path<'a> {
 
 #[cfg(feature = "alloc")]
 mod alloc_support {
-    use alloc::borrow::Cow;
+    use alloc::{boxed::Box, borrow::Cow};
 
     use super::*;
 

core/src/str.rs

@@ -339,7 +339,7 @@ impl<'k> serde::Serialize for Str<'k> {
 
 #[cfg(feature = "alloc")]
 mod alloc_support {
-    use alloc::borrow::Cow;
+    use alloc::{borrow::{Cow, ToOwned}, string::String};
 
     use super::*;
 

core/src/template.rs

@@ -660,6 +660,8 @@ enum PartKind<'a> {
 mod alloc_support {
     use super::*;
 
+    use alloc::vec::Vec;
+
     impl Template<'static> {
         /**
         Create a template from a set of owned parts.

core/src/value.rs

@@ -168,6 +168,8 @@ impl<'v> Value<'v> {
             fn visit_any(&mut self, value: value_bag::ValueBag) -> Result<(), value_bag::Error> {
                 #[cfg(feature = "alloc")]
                 {
+                    use alloc::string::ToString;
+
                     self.0 = value.to_string().parse().ok();
 
                     Ok(())
@@ -420,7 +422,7 @@ impl ToValue for (dyn std::error::Error + 'static) {
 mod alloc_support {
     use super::*;
 
-    use alloc::borrow::Cow;
+    use alloc::{borrow::Cow, vec::Vec};
 
     impl<'v> Value<'v> {
         /**