ruby - Can't install mysql gem on OS X

Question

I'm doing a

sudo gem install mysql

on OS X to install the mysql gem. This fails with the following output:

Building native extensions. This could take a while...

ERROR: Error installing mysql:

ERROR: Failed to build gem native extension.

/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby extconf.rb

checking for mysql_ssl_set()... yes

checking for rb_str_set_len()... yes

checking for rb_thread_start_timer()... no

checking for mysql.h... yes

creating Makefile

make "DESTDIR=" clean

make "DESTDIR="

compiling mysql.c

linking shared-object mysql/mysql_api.bundle

clang: error: unknown argument: '-multiply_definedsuppress' [-Wunused-command-line-> argument-hard-error-in-future]

clang: note: this will be a hard error (cannot be downgraded to a warning) in the future

make: * [mysql_api.bundle] Error 1

make failed, exit code 2

Gem files will remain installed in /Library/Ruby/Gems/2.0.0/gems/mysql-2.9.1 for inspection.

Results logged to /Library/Ruby/Gems/2.0.0/extensions/universal-darwin-13/2.0.0/mysql-2.9.1/gem_make.out

Any idea what could be causing this? I have mysql installed with homebrew if that makes a difference.

Answer 1

From Apple's Xcode/Clang release notes:

The Apple LLVM compiler in Xcode 5.1 treats unrecognized command-line options as errors. This issue has been seen when building both Python native extensions and Ruby Gems, where some invalid compiler options are currently specified. Projects using invalid compiler options will need to be changed to remove those options. To help ?ease that transition, the compiler will temporarily accept an option to downgrade the error to a warning:

-Wno-error=unused-command-line-argument-hard-error-in-future

ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future gem install GemName