netCDF: option for C++ bindings

Closes #15264.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Library/Formula/netcdf.rb

@@ -6,6 +6,12 @@ class NetcdfCXX < Formula
   sha1 '59628c9f06c211a47517fc00d8b068da159ffa9d'
 end
 
+class NetcdfCXX_compat < Formula
+  homepage 'http://www.unidata.ucar.edu/software/netcdf'
+  url 'http://www.unidata.ucar.edu/downloads/netcdf/ftp/netcdf-cxx-4.2.tar.gz'
+  sha1 'bab9b2d873acdddbdbf07ab35481cd0267a3363b'
+end
+
 class NetcdfFortran < Formula
   homepage 'http://www.unidata.ucar.edu/software/netcdf'
   url 'http://www.unidata.ucar.edu/downloads/netcdf/ftp/netcdf-fortran-4.2.tar.gz'
@@ -19,8 +25,9 @@ class Netcdf < Formula
 
   depends_on 'hdf5'
 
-  option 'enable-fortran', 'Compile Fortran Bindings'
+  option 'enable-fortran', 'Compile Fortran bindings'
   option 'disable-cxx', "Don't compile C++ bindings"
+  option 'enable-cxx-compat', 'Compile C++ bindings for compatibility'
 
   def install
     if build.include? 'enable-fortran'
@@ -56,6 +63,11 @@ def install
       system 'make install'
     end unless build.include? 'disable-cxx'
 
+    NetcdfCXX_compat.new.brew do
+      system './configure', *common_args
+      system 'make install'
+    end if build.include? 'enable-cxx-compat'
+
     NetcdfFortran.new.brew do
       system './configure', *common_args
       system 'make install'