zlib@1.2.10 and R do not get along, work around it (#2727)

* zlib@1.2.10 and R do not get along, work around it

R's configure script has trouble with version numbers > 1.2.9.

This works around it by constraining R to 1.2.8.

I'm working with some R folk on getting it fixed going forward.

* Add adamjstewart's change.

var/spack/repos/builtin/packages/R/package.py

@@ -63,6 +63,7 @@ class R(Package):
     depends_on('icu4c')
     depends_on('glib')
     depends_on('zlib')
+    depends_on('zlib@:1.2.8', when='@:3.3.1')
     depends_on('bzip2')
     depends_on('libtiff')
     depends_on('jpeg')