With this change, you can now cross compile test cases and run
them on qemu-user. Here is an example to run our test suits in
an emulated ARM32 environment.
$ CC=arm-linux-gnueabihf-gcc \
CXX=arm-linux-gnueabihf-g++ \
GCC=arm-linux-gnueabihf-gcc \
GXX=arm-linux-gnueabihf-g++ \
OBJDUMP=arm-linux-gnueabihf-objdump \
MACHINE=arm \
QEMU='qemu-arm -L /usr/arm-linux-gnueabihf' \
make -j16 test
We unset `LANG`, but it looks like `LC_ALL` takes precedence over `LANG`,
so we should set `LC_ALL` to `C`.
Reported at https://github.com/rui314/mold/pull/385