Change the global allocators used by dylibs

jemalloc was removed from the standard library recently:
<rust-lang/rust#55238>

Removed `extern crate alloc_system;` from `ngsloader` because this is
the current default choice.

`ngsengine` explicitly registers jemalloc (provided by the
`jemallocator` crate) as the global allocator for optimal runtime
performance.

Author: yvt

EngineCore/Cargo.lock

@@ -14,3 +14,7 @@ ngscom = { path = "../ngscom" }
 ngspf = { path = "../ngspf" }
 ngspf_com = { path = "../ngspf/src/com" }
 cgmath = "0.16.1"
+
+[dependencies.jemallocator]
+version = "0.1.9"
+features = ["unprefixed_malloc_on_supported_platforms"]

EngineCore/src/ngsengine/Cargo.toml

@@ -6,3 +6,7 @@
 mod entry;
 
 pub use self::entry::ngsengine_create;
+
+// Register jemalloc as the global allocator
+#[global_allocator]
+static ALLOC: jemallocator::Jemalloc = jemallocator::Jemalloc;

EngineCore/src/ngsengine/src/lib.rs

@@ -12,10 +12,6 @@
 //!
 //! [`ngsengine`]: ../ngsengine/index.html
 //!
-// Use the system allocator - we don't want two instances of jemalloc running
-// simultaneously! Besides, we don't care about the allocator's performance here.
-#![feature(alloc_system)]
-extern crate alloc_system;
 
 use ngsbase::INgsProcessorInfo;
 use ngscom::{hresults, BStringRef, ComPtr, HResult};