the environment of run-tests.
* examples/rsa-encrypt-test: Use $EXEEXT and $EMULATOR.
* examples/rsa-sign-test: Likewise.
* examples/rsa-verify-test: Likewise.
* examples/setup-env: Likewise.

Rev: nettle/examples/Makefile.in:1.10
Rev: nettle/examples/rsa-encrypt-test:1.2
Rev: nettle/examples/rsa-sign-test:1.2
Rev: nettle/examples/rsa-verify-test:1.2
Rev: nettle/examples/setup-env:1.2
Rev: nettle/examples/teardown-env:1.2