我正在尝试在项目中安装此 ope-rb gem。在这里， native.c 是看起来像是gem的源程序。由于找不到 openssl / rand.h 头文件，因此将引发错误。谁能告诉我我想念什么？
Fetching ope-rb 0.0.1
Installing ope-rb 0.0.1 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
/Users/matheswka/.rvm/rubies/ruby-2.2.0/bin/ruby -r ./siteconf20180821-27089-1aspxw9.rb extconf.rb
checking for openssl/ssl.h... no
checking for SSLv23_method() in -lssl... yes
creating Makefile
make "DESTDIR=" clean
make "DESTDIR="
compiling native.c
native.c:3:10: fatal error: 'openssl/rand.h' file not found
#include <openssl/rand.h>
^~~~~~~~~~~~~~~~
1 error generated.
make: *** [native.o] Error 1
make failed, exit code 2
Gem files will remain installed in /Users/matheswka/.rvm/gems/ruby-2.2.0@appointments/gems/ope-rb-0.0.1 for inspection.
Results logged to /Users/matheswka/.rvm/gems/ruby-2.2.0@appointments/extensions/x86_64-darwin-14/2.2.0-static/ope-rb-0.0.1/gem_make.out
An error occurred while installing ope-rb (0.0.1), and Bundler cannot continue.
Make sure that `gem install ope-rb -v '0.0.1'` succeeds before bundling.