← Adarsh Pandit →

After updating to El Capitan, installing new gems started to fail. It looked something like this:

Building native extensions.  This could take a while...
ERROR:  Error installing awesome_gem_name:
    ERROR: Failed to build gem native extension.

checking for rb_trap_immediate in ruby.h,rubysig.h... no
checking for rb_thread_blocking_region()... no
...
CFLAGS=-O3 -I/Users/haven/.sm/pkg/active/include -fPIC -mmacosx-version-min=10.7 -pipe  -Wall -Wextra -Wno-deprecated-declarations -Wno-ignored-qualifiers -Wno-unused-result
CPPFLAGS=-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

But here’s the important part:

In file included from binder.cpp:20:
./project.h:116:10: fatal error: 'openssl/ssl.h' file not found

Wha happened?

As of OS X El Capitan, Apple no longer provides OpenSSL headers.

“But wait, I have OpenSSL!,” you cry.

$ which openssl
/usr/bin/openssl

Yes you do, but you lack the C headers which some gems use to build native extensions.

Think of the headers as the source code and /usr/bin/openssl as the compiled binary.

Apple no longer ships the headers on which many gems with native C extensions depend. For more on why, read this post

# On earlier OS X:
$ ls /usr/include/openssl/ssl.h
/usr/include/openssl/ssl.h

# On El Capitan:
$ ls /usr/include/openssl/ssl.h
ls: /usr/include/ssl.h: No such file or directory

Fix It!

You can install your own OpenSSL headers using either Homebrew or MacPorts. I’m a Homebrew guy so let’s go that route.

First let’s uninstall whatever you have, if anything:

$ brew uninstall openssl --force

The --force bit will “remove out-of-date keg-only brews as well” (see the man brew page).

I couldn’t get this to work unless I updated my XCode Command Line tools after upgrading to El Capitan.

So let’s do that:

$ xcode-select --install

Be sure to agree to everything, not just in the dialogue boxes OS X presents, but in life - just try to say yes more. (NOTE: Any philosophical disagreements are beyond the scope of this blog post and left as an exercise for the reader.)

When that is finished, then install OpenSSL and force symlinking into the appropriate places:

$ brew update
$ brew install openssl
$ brew link --force openssl

Now your bundle install should work no problem!

Acknowledgements

Thanks to Gabe Berke-Williams for helpful edits. Read his amazing blog or follow his pun-filled Twitter feed or investigate his myriad of interesting GitHub projects.