Undefined method 'captures' during installation

```
Fetching: nmatrix-0.0.9.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing nmatrix:
	ERROR: Failed to build gem native extension.

    /Users/sheerun/.rbenv/versions/2.0.0-p247/bin/ruby extconf.rb
checking for main() in -llapack... yes
checking for main() in -lcblas... yes
checking for main() in -latlas... no
checking for clapack.h... no
checking for cblas.h... no
checking for cblas.h in /usr/local/atlas/include,/usr/include/atlas... no
checking for cblas.h... no
checking for clapack_dgetrf() in cblas.h,clapack.h... no
checking for clapack_dgetri() in cblas.h,clapack.h... no
checking for dgesvd_() in clapack.h... no
checking for cblas_dgemm() in cblas.h... no
Exception `NoMethodError' at extconf.rb:205 - undefined method `captures' for nil:NilClass
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
	--with-opt-dir
	--without-opt-dir
	--with-opt-include
	--without-opt-include=${opt-dir}/include
	--with-opt-lib
	--without-opt-lib=${opt-dir}/lib
	--with-make-prog
	--without-make-prog
	--srcdir=.
	--curdir
	--ruby=/Users/sheerun/.rbenv/versions/2.0.0-p247/bin/ruby
	--with-lapacklib
	--without-lapacklib
	--with-cblaslib
	--without-cblaslib
	--with-atlaslib
	--without-atlaslib
	--with-atlas-dir
	--without-atlas-dir
	--with-atlas-include
	--without-atlas-include=${atlas-dir}/include
	--with-atlas-lib
	--without-atlas-lib=${atlas-dir}/
extconf.rb:205:in `gplusplus_version': undefined method `captures' for nil:NilClass (NoMethodError)
	from extconf.rb:213:in `<main>'
```

```
ruby -v
ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-darwin13.0.1]
```

```
gcc -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)
Target: x86_64-apple-darwin13.0.1
Thread model: posix
```

```
clang -v
Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)
Target: x86_64-apple-darwin13.0.1
Thread model: posix
```

The system is Mavericks 10.9 (not upgraded).