Fix system Ruby (2.0.0) on OS X 10.9.

README.md

Fix Apple's mess. They built Ruby in a custom way that has lead to these options not containing the original commas anymore, which when combined with the change they made to clang (in Xcode 5.1) to error out on unrecognized options leads to failing builds.

This is what a typical build failure will look like:

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: *** [foo.bundle] Error 1

To fix this, apply the patch like so (or manually download the patch):

$ curl -O https://gist.githubusercontent.com/alloy/9857708/raw/bd693fdf88b9c15a5667ca7a3d338c61edd674ff/osx-10.9-ruby-2.0.0-config-fix.diff
$ sudo patch /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/universal-darwin13/rbconfig.rb osx-10.9-ruby-2.0.0-config-fix.diff
patching file /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/universal-darwin13/rbconfig.rb

osx-10.9-ruby-2.0.0-config-fix.diff

--- rbconfig.rb.osx-orig	2014-03-29 17:26:53.000000000 +0100
+++ rbconfig.rb	2014-03-29 17:32:26.000000000 +0100
@@ -122,7 +122,7 @@
   CONFIG["CCDLFLAGS"] = ""
   CONFIG["STATIC"] = ""
   CONFIG["ARCH_FLAG"] = arch_flag || " #{arch_flag} "
-  CONFIG["DLDFLAGS"] = "-undefineddynamic_lookup -multiply_definedsuppress"
+  CONFIG["DLDFLAGS"] = "-undefined dynamic_lookup -multiply_defined suppress"
   CONFIG["ALLOCA"] = ""
   CONFIG["codesign"] = "codesign"
   CONFIG["POSTLINK"] = "test -z '$(RUBY_CODESIGN)' || codesign -s '$(RUBY_CODESIGN)' -f $@"

Looks like the line starting with CONFIG["LIBRUBY_DLDFLAGS"] (i.e., L82) needs patching in the same way.

@sharplet While it has the same issue indeed, it’s afaik not used for anything.