R包rgdal/rgeos"不可用(对于R版本3.1.1)"

难以在OSX Mavericks的新R版本中安装某些软件包.两者rgeos并rgdal返回例如:

package 'rgeos' is available as a source package but not as a binary

Warning in install.packages :
  package 'rgeos' is not available (for R version 3.1.1)

在我的Windows系统上,两个软件包都安装了R 3.1.1,这是一个Mavericks/OSX版本问题,还是我的构建问题？更改库存储库没有任何区别.我已经看过从二进制文件构建,但是例如在rgeos主页上它说"OS X Mavericks二进制文件:r-release:not available"所以我已经搞砸了.

感谢您的建议.

编辑:

尝试@Andrie的建议:

> install.packages('rgeos', type='source')
Installing package into ‘/Users/robinedwards/Library/R/3.1/library’
(as ‘lib’ is unspecified)
trying URL 'http://cran.ma.imperial.ac.uk/src/contrib/rgeos_0.3-6.tar.gz'
Content type 'application/x-gzip' length 240510 bytes (234 Kb)
opened URL
==================================================
downloaded 234 Kb

* installing *source* package ‘rgeos’ ...
** package ‘rgeos’ successfully unpacked and MD5 sums checked
configure: CC: clang
configure: CXX: clang++
configure: rgeos: 0.3-4
checking for /usr/bin/svnversion... yes
configure: svn revision: 450
checking geos-config usability... 
./configure: line 2056: geos-config: command not found
no
configure: error: geos-config not usable
ERROR: configuration failed for package ‘rgeos’
* removing ‘/Users/robinedwards/Library/R/3.1/library/rgeos’
Warning in install.packages :
  installation of package ‘rgeos’ had non-zero exit status

The downloaded source packages are in
    ‘/private/var/folders/_s/ppznw4sx7p51kwv__hj3d8540000gn/T/RtmpK40xj7/downloaded_packages’

以及构建页面的屏幕截图: