Add R package.

var/spack/packages/R/package.py

+from spack import *
+
+class R(Package):
+    """R is 'GNU S', a freely available language and environment for
+       statistical computing and graphics which provides a wide va
+       riety of statistical and graphical techniques: linear and
+       nonlinear modelling, statistical tests, time series analysis,
+       classification, clustering, etc. Please consult the R project
+       homepage for further information."""
+    homepage = "http://www.example.com"
+    url      = "http://cran.cnr.berkeley.edu/src/base/R-3/R-3.1.2.tar.gz"
+
+    version('3.1.2', '3af29ec06704cbd08d4ba8d69250ae74')
+
+    depends_on("readline")
+    depends_on("ncurses")
+    depends_on("icu")
+    depends_on("glib")
+    depends_on("zlib")
+    depends_on("libtiff")
+    depends_on("jpeg")
+    depends_on("cairo")
+    depends_on("pango")
+    depends_on("freetype")
+    depends_on("tcl")
+    depends_on("tk")
+
+    def install(self, spec, prefix):
+        configure("--prefix=%s" % prefix,
+                  "--enable-R-shlib",
+                  "--enable-BLAS-shlib")
+        make()
+        make("install")