Only pass `-C default-linker-libraries` with sanitizers

This'll help retain test compatibility until 1.31.0 is released!

configure.ac

@@ -1210,17 +1210,17 @@ dnl variable.
 RUST_LINKER_OPTIONS=""
 if test "x$have_clang" = "xyes"; then
 	if test "x$CFLAGS_ASAN" != "x"; then
-		RUST_LINKER_OPTIONS="$RUST_LINKER_OPTIONS -Clink-arg=$CFLAGS_ASAN"
+		RUST_LINKER_OPTIONS="$RUST_LINKER_OPTIONS -Clink-arg=$CFLAGS_ASAN -Cdefault-linker-libraries"
 	fi
 	if test "x$CFLAGS_UBSAN" != "x"; then
-        	RUST_LINKER_OPTIONS="$RUST_LINKER_OPTIONS -Clink-arg=$CFLAGS_UBSAN"
+        	RUST_LINKER_OPTIONS="$RUST_LINKER_OPTIONS -Clink-arg=$CFLAGS_UBSAN -Cdefault-linker-libraries"
 	fi
 else
 	if test "x$CFLAGS_ASAN" != "x"; then
-		RUST_LINKER_OPTIONS="$RUST_LINKER_OPTIONS -Clink-arg=-fsanitize=address"
+		RUST_LINKER_OPTIONS="$RUST_LINKER_OPTIONS -Clink-arg=-fsanitize=address -Cdefault-linker-libraries"
 	fi
 	if test "x$CFLAGS_UBSAN" != "x"; then
-        	RUST_LINKER_OPTIONS="$RUST_LINKER_OPTIONS -Clink-arg=-fsanitize=undefined"
+        	RUST_LINKER_OPTIONS="$RUST_LINKER_OPTIONS -Clink-arg=-fsanitize=undefined -Cdefault-linker-libraries"
 	fi
 fi
 AC_SUBST(RUST_LINKER_OPTIONS)

src/test/include.am

@@ -12,7 +12,7 @@ TESTS_ENVIRONMENT = \
 	export EXTRA_CARGO_OPTIONS="$(EXTRA_CARGO_OPTIONS)"; \
 	export CARGO_ONLINE="$(CARGO_ONLINE)"; \
 	export CCLD="$(CCLD)"; \
-	export RUSTFLAGS="-C linker=`echo '$(CC)' | cut -d' ' -f 1` $(RUST_LINKER_OPTIONS) -C default-linker-libraries";
+	export RUSTFLAGS="-C linker=`echo '$(CC)' | cut -d' ' -f 1` $(RUST_LINKER_OPTIONS)";
 
 TESTSCRIPTS = \
 	src/test/fuzz_static_testcases.sh \