Error install eventmachine

gistfile1.txt

An error occurred while installing eventmachine (1.0.8), and Bundler cannot continue.
Make sure that `gem install eventmachine -v '1.0.8'` succeeds before bundling.
➜  echobind git:(gif-optimations) gem install eventmachine -v '1.0.8'
/usr/local/var/rbenv/versions/2.1.4/bin/ruby: warning: RUBY_HEAP_MIN_SLOTS is obsolete. Use RUBY_GC_HEAP_INIT_SLOTS instead.
Building native extensions.  This could take a while...
ERROR:  Error installing eventmachine:
    ERROR: Failed to build gem native extension.

    /usr/local/var/rbenv/versions/2.1.4/bin/ruby extconf.rb
/usr/local/var/rbenv/versions/2.1.4/bin/ruby: warning: RUBY_HEAP_MIN_SLOTS is obsolete. Use RUBY_GC_HEAP_INIT_SLOTS instead.
checking for rb_trap_immediate in ruby.h,rubysig.h... no
checking for rb_thread_blocking_region()... yes
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 pipe2() in unistd.h... no
checking for accept4() in sys/socket.h... no
checking for SOCK_CLOEXEC in sys/socket.h... no
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
CFLAGS= -O3 -Wno-error=shorten-64-to-32  -pipe  -Wall -Wextra -Wno-deprecated-declarations -Wno-ignored-qualifiers -Wno-unused-result
CPPFLAGS=-I/usr/local/var/rbenv/versions/2.1.4/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT $(DEFS) $(cppflags) -Wall -Wextra -Wno-deprecated-declarations -Wno-ignored-qualifiers -Wno-unused-result
checking for clock_gettime()... no
checking for gethrtime()... no
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 /usr/local/var/rbenv/versions/2.1.4/lib/ruby/gems/2.1.0/gems/eventmachine-1.0.8 for inspection.
Results logged to /usr/local/var/rbenv/versions/2.1.4/lib/ruby/gems/2.1.0/extensions/x86_64-darwin-15/2.1.0-static/eventmachine-1.0.8/gem_make.out
➜  echobind git:(gif-optimations)