LTO kills the build on 32-bit architectures.

--- firefox-128.0/config/makefiles/rust.mk.old	2024-07-04 11:20:25.000000000 -0500
+++ firefox-128.0/config/makefiles/rust.mk	2024-08-04 03:20:25.375459833 -0500
@@ -82,25 +82,6 @@
 # These flags are passed via `cargo rustc` and only apply to the final rustc
 # invocation (i.e., only the top-level crate, not its dependencies).
 cargo_rustc_flags = $(CARGO_RUSTCFLAGS)
-ifndef DEVELOPER_OPTIONS
-ifndef MOZ_DEBUG_RUST
-# Enable link-time optimization for release builds, but not when linking
-# gkrust_gtest. And not when doing cross-language LTO.
-ifndef MOZ_LTO_RUST_CROSS
-# Never enable when sancov is enabled to work around https://github.com/rust-lang/rust/issues/90300.
-ifndef rustflags_sancov
-# Never enable when coverage is enabled to work around https://github.com/rust-lang/rust/issues/90045.
-ifndef MOZ_CODE_COVERAGE
-ifeq (,$(findstring gkrust_gtest,$(RUST_LIBRARY_FILE)))
-cargo_rustc_flags += -Clto$(if $(filter full,$(MOZ_LTO_RUST_CROSS)),=fat)
-endif
-# We need -Cembed-bitcode=yes for all crates when using -Clto.
-RUSTFLAGS += -Cembed-bitcode=yes
-endif
-endif
-endif
-endif
-endif
 
 ifdef CARGO_INCREMENTAL
 export CARGO_INCREMENTAL