r33838 breaks on OSX 10.7 with Xcode 4.2:

> % svn up -r33837 configure.in ; make reconfig
> ...
> checking for nroff... /usr/bin/nroff
> .ext/include/x86_64-darwin11.2.0/ruby/config.h unchanged
> ruby library version = 1.9.1
> configure: creating ./config.status
> config.status: creating Makefile
> config.status: creating ruby-1.9.pc
> 
> % svn up -r33838 configure.in ; make reconfig
> ...
> checking for strip... strip
> ./configure: line 39682: syntax error near unexpected token `newline'
> ./configure: line 39682: `  *' -Xlinker --no-undefined '*'
> make: *** [config.status] Error 2
> 
> % autoconf -V
> autoconf (GNU Autoconf) 2.61
> ...

It looks like it is generating a syntax error in the case statement:

>   # RUBY_APPEND_OPTION(EXTLDFLAGS, -Xlinker --no-undefined)
> 	case " ${EXTLDFLAGS-} " in
>   *' -Xlinker --no-undefined '*
> 	{ echo "$as_me:$LINENO: result: yes" >&5
> echo "${ECHO_T}yes" >&6; }

But I don't know autoconf at all, so I'm hesitant to try to hack on this.