Copycat attempt to support OpenBSD, based on #116.

[nickpelone]

I don't know how to extensively test this, but things like value-bag and log 0.4.14 now compile on OpenBSD with this. (and the programs using them do not immediately explode)

I encountered the need for this today when trying to build a project who uses async-std, who eventually (via async-io) pulls in the log crate who switched to using value-bag, which then uses this crate.

Let me know what I can do to improve this further if needed. Thank you!

[nickpelone]

After my latest commit(6b58a07), all the tests appear to pass:

   Compiling ctor v0.1.18 (/var/user/rust-ctor/ctor)
   Compiling tests v0.1.0 (/var/user/rust-ctor/tests)
    Finished test [unoptimized + debuginfo] target(s) in 4.30s
     Running target/debug/deps/ctor-f9a210ca3f71b551

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

     Running target/debug/deps/tests-2f1cf760cb3b5396

running 2 tests
test test::test_initialized ... ok
test test::test_dylib ... ok

test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

We don't test shutdown, but if you see this message it worked!
   Doc-tests ctor

running 5 tests
test src/lib.rs - ctor (line 101) ... ok
test src/lib.rs - ctor (line 44) ... ok
test src/lib.rs - ctor (line 60) ... ok
test src/lib.rs - dtor (line 265) ... ok
test src/lib.rs - ctor (line 75) ... ok

test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

   Doc-tests tests

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

[mmastrac]

I can't necessarily test this myself either, but I'll approve based on your test output that looks correct. Thanks for this contribution!

[mmastrac]

Released as 0.1.19

[nickpelone]

Thank you very much for the prompt approval! Really appreciate it.