Add -Wundef to gcc's --strict-warnings options

[bernd-edlinger]

This PR adds -Wundef to --strict-warnings for gcc.
This warns on #if with undefined macros.

For 1.1.0-stable only.
I will do another PR for master once #2705 is merged.

[richsalz]

Because I'm lazy, what was undef'd?

[bernd-edlinger]

OPENSSL_API_COMPAT and __STDC_VERSION__ in pedantic mode
there was a discussion on the gcc mailing list, that
-Wundef should be silent on predefined macros,
but I don't know if anybody cared to implement that.

[richsalz]

Please add this to clang strict warnings too.

[bernd-edlinger]

Ok, does clang have -Wundef? And what is clang by the way :-)

[richsalz]

#2705 is merged, 7c6335a. You're kidding about clang, I assume.

[dot-asm]

Side note. If #2712 was broken to two commits, then it would be possible to cherry-pick one to 1.1.0 so that one wouldn't have to have separate request. Cherry-picks should be preferred way as it gives same modification same "tracking number"...

[bernd-edlinger]

@dot-asm I will keep that in mind; when I started I had the impression that 1.1.0 and master
are too different for a single commit. I will try to do smaller commits in the future.

Now I see two issues in the Travis CI build:
the gcc build fails here:

apps/rehash.c: In function 'ends_with_dirsep':
apps/rehash.c:277:8: error: "_WIN32" is not defined [-Werror=undef]
 # elif _WIN32

that elif _WIN32 was not there in my tree, but CI did a rebase apparently,
so I will do that as well.

I need to change that to elif defined(_WIN32)

In one clang build a different error happens, here:

crypto/o_str.c:230:8: error: '_POSIX_C_SOURCE' is not defined, evaluates to 0 [-Werror,-Wundef]
#elif (_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
crypto/o_str.c:230:38: error: '_XOPEN_SOURCE' is not defined, evaluates to 0 [-Werror,-Wundef]
#elif (_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)

I will add two single commits for each.

[levitte]

Now I see two issues in the Travis CI build:
the gcc build fails here:

apps/rehash.c: In function 'ends_with_dirsep':
apps/rehash.c:277:8: error: "_WIN32" is not defined [-Werror=undef]
 # elif _WIN32

Good catch. Fix in #2727

[levitte]

In one clang build a different error happens, here:

crypto/o_str.c:230:8: error: '_POSIX_C_SOURCE' is not defined, evaluates to 0 [-Werror,-Wundef]
#elif (_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
crypto/o_str.c:230:38: error: '_XOPEN_SOURCE' is not defined, evaluates to 0 [-Werror,-Wundef]
#elif (_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)

I'm curious, on what configuration was that? grep perlarg configdata.pm will show what Configure was hit with.

[bernd-edlinger]

I'm curious, on what configuration was that? grep perlarg configdata.pm will show what Configure was hit with.

I think it was with "no-stdio --strict-warnings" BUILDONLY="yes"

[richsalz]

4c3376e in 1.1.0 thanks!