Installing EventMachine on Mac OSX

Robs-iMac:pledge_core roblacey$ gem install eventmachine -v 1.0.7
Building native extensions.  This could take a while...
ERROR:  Error installing eventmachine:
	ERROR: Failed to build gem native extension.

    /Users/roblacey/.rvm/rubies/ruby-2.2.2/bin/ruby -r ./siteconf20161214-75988-ryo2ti.rb extconf.rb
checking for rb_trap_immediate in ruby.h,rubysig.h... no
checking for rb_thread_blocking_region()... no
checking for ruby/thread.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for inotify_init() in sys/inotify.h... no
checking for __NR_inotify_init in sys/syscall.h... no
checking for writev() in sys/uio.h... yes
checking for rb_thread_fd_select()... yes
checking for rb_fdset_t in ruby/intern.h... yes
checking for rb_wait_for_single_fd()... yes
checking for rb_enable_interrupt()... no
checking for rb_time_new()... yes
checking for sys/event.h... yes
checking for sys/queue.h... yes
checking for clock_gettime()... yes
checking for CLOCK_MONOTONIC_RAW in time.h... yes
checking for CLOCK_MONOTONIC in time.h... yes
creating Makefile

make "DESTDIR=" clean

make "DESTDIR="
compiling binder.cpp
In file included from binder.cpp:20:
./project.h:116:10: fatal error: 'openssl/ssl.h' file not found
#include <openssl/ssl.h>
         ^
1 error generated.
make: *** [binder.o] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/roblacey/.rvm/gems/ruby-2.2.2@rails41-trunk/gems/eventmachine-1.0.7 for inspection.
Results logged to /Users/roblacey/.rvm/gems/ruby-2.2.2@rails41-trunk/extensions/x86_64-darwin-14/2.2.0-static/eventmachine-1.0.7/gem_make.out
Robs-iMac:pledge_core roblacey$ cat /Users/roblacey/.rvm/gems/ruby-2.2.2@rails41-trunk/extensions/x86_64-darwin-14/2.2.0-static/eventmachine-1.0.7/gem_make.out
/Users/roblacey/.rvm/rubies/ruby-2.2.2/bin/ruby -r ./siteconf20161214-75988-ryo2ti.rb extconf.rb
checking for rb_trap_immediate in ruby.h,rubysig.h... no
checking for rb_thread_blocking_region()... no
checking for ruby/thread.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for inotify_init() in sys/inotify.h... no
checking for __NR_inotify_init in sys/syscall.h... no
checking for writev() in sys/uio.h... yes
checking for rb_thread_fd_select()... yes
checking for rb_fdset_t in ruby/intern.h... yes
checking for rb_wait_for_single_fd()... yes
checking for rb_enable_interrupt()... no
checking for rb_time_new()... yes
checking for sys/event.h... yes
checking for sys/queue.h... yes
checking for clock_gettime()... yes
checking for CLOCK_MONOTONIC_RAW in time.h... yes
checking for CLOCK_MONOTONIC in time.h... yes
creating Makefile

make "DESTDIR=" clean

make "DESTDIR="
compiling binder.cpp
In file included from binder.cpp:20:
./project.h:116:10: fatal error: 'openssl/ssl.h' file not found
#include <openssl/ssl.h>
         ^
1 error generated.
make: *** [binder.o] Error 1

make failed, exit code 2
Robs-iMac:pledge_core roblacey$ gem install eventmachine -v '1.0.7' -- --with-cppflags=-I/usr/local/opt/openssl/include
Building native extensions with: '--with-cppflags=-I/usr/local/opt/openssl/include'
This could take a while...
Successfully installed eventmachine-1.0.7
Parsing documentation for eventmachine-1.0.7
Installing ri documentation for eventmachine-1.0.7
Done installing documentation for eventmachine after 4 seconds
1 gem installed