Avoid the direct use of 'defined' in macro expansion

[juergenhoetzel]

Fixes "-Wexpansion-to-defined" warnings produced by clang >=3.9.

Closes #4537

[claudioandre-br]

Passes upstream Travis CI: https://travis-ci.org/github/claudioandre-br/JohnTheRipper/builds/753171495

BTW: if Travis' plan is NOT based on Linux credits (if the organization can run unlimited builds using Linux), there is no reason to skip all builds on a PR as it is doing now.

[solardiz]

BTW: if Travis' plan is NOT based on Linux credits (if the organization can run unlimited builds using Linux), there is no reason to skip all builds on a PR as it is doing now.

What is it skipping now? I see "Travis CI - Pull Request Successful in 5m — Build Passed", perhaps after your approval of the PR's changes. By skipping do you mean this being conditional on approval?

[solardiz]

Nitpick: there are extra braces around the expressions - these made sense in the #define lines, but are unneeded in #if. Anyway, I'll merge this as-is because we currently have a build error that we need to fix ASAP.

[solardiz]

Should these changes perhaps be contributed upstream, to @floodyberry's https://github.com/floodyberry/poly1305-donna? @juergenhoetzel Will you do that, please? Thanks!

[claudioandre-br]

What is it skipping now? I see "Travis CI - Pull Request Successful in 5m — Build Passed"

It is skipping the build (configure + make).
See, for example, Mac; the execution took 23s. Linux, 40s. The only thing that happened was a boot, a check and an exit 0.

• https://travis-ci.com/github/openwall/john/builds/212175034

The merged code is, in fact, being built.