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/Android.bp b/rialto/Android.bp
index 326f6fc..12d6e7b 100644
--- a/rialto/Android.bp
+++ b/rialto/Android.bp
@@ -13,6 +13,7 @@
"libbssl_ffi_nostd",
"libciborium_io_nostd",
"libciborium_nostd",
+ "libcstr",
"libdiced_open_dice_nostd",
"libdiced_sample_inputs_nostd",
"libhyp",