[OSX] fix brew openssl detection

[jonasschnelli]

ping @theuni (not sure if I did this correct, it seems like extending PKG_CONFIG_PATH does not work for a later header check with AC_CHECK_HEADER).

OSX slowly depractates openssl. Since 10.11.3, not event Xcode installs the openssl headers. This PR will allow using homebrews openssl headers.

[jameshilliard]

The workaround I've used is:

brew link openssl --force

[jonasschnelli]

The force linking is also a good idea, though, I think if we detect brews OpenSSL pkgconf, we should also allow to detect the headers in brews OpenSSL path.

[jameshilliard]

I think this is how you would do that properly.

[jonasschnelli]

@jameshilliard I think this PR would do it exactly as recommended in you link.

[jameshilliard]

Doesn't it need $(brew --prefix) in the include path for keg only openssl?

[jonasschnelli]

Check: https://github.com/bitcoin/bitcoin/pull/7560/files#diff-67e997bcfdac55191033d57a16d1408aL281

[laanwj]

@theuni can you take a look here?

[theuni]

@jonasschnelli hmm, appending PKG_CONFIG_PATH should be enough to pick up on the openssl headers (that's what it's there for). In the header check, we first set CFLAGS="$CFLAGS $SSL_CFLAGS $CRYPTO_CFLAGS", which should add whatever pkg-config finds.

So your change shouldn't be necessary, seems to me something else is broken.

Could you please paste the relevant failure from config.log?

[jonasschnelli]

Cannot reproduce the issue anymore. It was probably a local-only thing.
Thanks @theuni!