xcode - 'openssl/conf.h' file not found error on MacOS Sierra -

i working on c++ project uses boost asio. trying build libraries use asia, getting following error

/usr/local/include/boost/asio/ssl/detail/openssl_types.hpp:19:10: fatal error: 'openssl/conf.h' file not found #include <openssl/conf.h> 

looking of solutions here & here, tried

brew install openssl brew link openssl --force xcode-select --install 

but didn't help.

doing following doesn't seem work

export c_include_path=/usr/local/include export cplus_include_path=/usr/local/include 

boost version using boost_1_63_0. on macos sierra xcode 8.3.1. have installed boost using homebrew

brew install boost 

as understand other links, xcode looking @ wrong place ssl headers. how can resolve this?

i looked /usr/local/include & /opt/local/include. 'openssl/ssl.h' not present in either locations. doing brew install openssl says following

warning: openssl keg-only , version linked opt. use `brew install --force` if want install version 

doing brew install openssl --force says

warning: openssl-1.0.2k installed, it's not linked. 

doing brew link openssl --force doesn't solve issue.

doig which openssl returns following:

/usr/local/bin/openssl 

please suggest

linked or not, installed homebrew packages reachable via link in /usr/local/opt. additionally, when install openssl via homebrew, homebrew tells how use openssl libraries , headers.

~ nega@rust 15s ❯ brew install openssl ==> downloading https://homebrew.bintray.com/bottles/openssl-1.0.2k.el_capitan.bottle.tar.gz downloaded: /users/nega/library/caches/homebrew/openssl-1.0.2k.el_capitan.bottle.tar.gz ==> pouring openssl-1.0.2k.el_capitan.bottle.tar.gz ==> using sandbox ==> caveats ca file has been bootstrapped using certificates systemroots keychain. add additional certificates (e.g. certificates added in system keychain), place .pem files in   /usr/local/etc/openssl/certs  , run   /usr/local/opt/openssl/bin/c_rehash  formula keg-only, means not symlinked /usr/local.  apple has deprecated use of openssl in favor of own tls , crypto libraries  if need have software first in path run:   echo 'export path="/usr/local/opt/openssl/bin:$path"' >> ~/.zshrc  compilers find software may need set:     ldflags:  -l/usr/local/opt/openssl/lib     cppflags: -i/usr/local/opt/openssl/include pkg-config find software may need set:     pkg_config_path: /usr/local/opt/openssl/lib/pkgconfig  ==> summary 🍺  /usr/local/cellar/openssl/1.0.2k: 1,696 files, 12mb  ~ nega@rust 11s ❯  

you don't need brew link anything. use directories homebrew tells in appropriate places in xcode , cmake.