libs: Move cstr!() into its own crate
Make the macro host_supported, for unittests.
This overshadows the homonymous crate from crates.io [1] but importing
and depending on an external crate for <10 lines of code seems overkill.
[1]: https://crates.io/crates/cstr
Bug: 308694211
Test: atest libcstr.tests
Test: m libcstr
Test: m pvmfw_bin rialto_bin vmbase_example_bin
Change-Id: If1bf37034fc004a380b3ba528b9d76393a865d3e
diff --git a/rialto/src/fdt.rs b/rialto/src/fdt.rs
index 8bb40c3..09cdd36 100644
--- a/rialto/src/fdt.rs
+++ b/rialto/src/fdt.rs
@@ -15,8 +15,8 @@
//! High-level FDT functions.
use core::ops::Range;
+use cstr::cstr;
use libfdt::{Fdt, FdtError};
-use vmbase::cstr;
/// Reads the DICE data range from the given `fdt`.
pub fn read_dice_range_from(fdt: &Fdt) -> libfdt::Result<Range<usize>> {