embedded: Remove error handler

Seems we no longer need an explicit error handler, remove it.

I did not grok the reason (long thread link below) but just removed it
and checked that the embedded crates still ran correctly.

rust-lang/rust#51540)

Author: tcharding

bitcoin/embedded/src/main.rs

@@ -8,7 +8,6 @@ extern crate bitcoin;
 
 use alloc::string::ToString;
 use alloc::vec;
-use core::alloc::Layout;
 use core::panic::PanicInfo;
 
 use alloc_cortex_m::CortexMHeap;
@@ -17,7 +16,6 @@ use bitcoin::{Address, Network, PrivateKey};
 use bitcoin::secp256k1::ffi::types::AlignedType;
 use bitcoin::secp256k1::Secp256k1;
 
-use cortex_m::asm;
 use cortex_m_rt::entry;
 use cortex_m_semihosting::{debug, hprintln};
 
@@ -57,16 +55,6 @@ fn main() -> ! {
     loop {}
 }
 
-// define what happens in an Out Of Memory (OOM) condition
-#[alloc_error_handler]
-fn alloc_error(_layout: Layout) -> ! {
-    hprintln!("alloc error").unwrap();
-    debug::exit(debug::EXIT_FAILURE);
-    asm::bkpt();
-
-    loop {}
-}
-
 #[inline(never)]
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {

hashes/embedded/src/main.rs

@@ -7,8 +7,6 @@ extern crate bitcoin_hashes;
 
 #[cfg(feature = "alloc")] extern crate alloc;
 #[cfg(feature = "alloc")] use alloc_cortex_m::CortexMHeap;
-#[cfg(feature = "alloc")] use core::alloc::Layout;
-#[cfg(feature = "alloc")] use cortex_m::asm;
 #[cfg(feature = "alloc")] use alloc::string::ToString;
 
 use bitcoin_hashes::{sha256, Hash, HashEngine};
@@ -63,12 +61,3 @@ fn check_result(engine: sha256::HashEngine) {
         debug::exit(debug::EXIT_FAILURE);
     }
 }
-
-// define what happens in an Out Of Memory (OOM) condition
-#[cfg(feature = "alloc")]
-#[alloc_error_handler]
-fn alloc_error(_layout: Layout) -> ! {
-    asm::bkpt();
-
-    loop {}
-}