Ensure crate is compiled with std for panic handler

This CL adds a patch to use `extern crate std` to ensure that a panic
handler is available when the crate is compiled as a dylib.

Test: m rust
Bug: 333887339
Change-Id: Ic444ca6b5bca12047a23aefe4df323b406a2ca5a

2 files changed, 17 insertions, 0 deletions

diff --git a/patches/std.patch b/patches/std.patch
new file mode 100644
index 0000000..76b5c02
--- /dev/null
+++ b/patches/std.patch
@@ -0,0 +1,14 @@
+diff --git a/src/lib.rs b/src/lib.rs
+index 4a17d3a..5493509 100644
+--- a/src/lib.rs
++++ b/src/lib.rs
+@@ -12,6 +12,9 @@
+ #![allow(clippy::eq_op)]
+ #![allow(clippy::assign_op_pattern)]
+ 
++#[cfg(android_dylib)]
++extern crate std;
++
+ mod libm_helper;
+ mod math;
+ 
diff --git a/src/lib.rs b/src/lib.rs
index 4a17d3a..5493509 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,6 +12,9 @@
 #![allow(clippy::eq_op)]
 #![allow(clippy::assign_op_pattern)]
 
+#[cfg(android_dylib)]
+extern crate std;
+
 mod libm_helper;
 mod math;