Bug 1742910 - Work around rust-lang/rust#90045. r=firefox-build-system-reviewers,andi

Differential Revision: https://phabricator.services.mozilla.com/D132111

Author: glandium

config/makefiles/rust.mk

@@ -94,6 +94,8 @@ ifndef MOZ_DEBUG_RUST
 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
 endif
@@ -103,6 +105,7 @@ endif
 endif
 endif
 endif
+endif
 
 ifdef CARGO_INCREMENTAL
 export CARGO_INCREMENTAL