Add opennurbs package (#6570)

* Adding OpenNurbs package.

* Fixing flake8 error.

* Removing unused os import from opennurbs.

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

+##############################################################################
+# Copyright (c) 2013-2017, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/spack/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License (as
+# published by the Free Software Foundation) version 2.1, February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+from spack import *
+import glob
+
+
+class Opennurbs(Package):
+    """OpenNURBS is an open-source NURBS-based geometric modeling library
+    and toolset, with meshing and display / output functions.
+    """
+
+    homepage = "https://github.com/OpenNURBS/OpenNURBS"
+    url      = "https://github.com/OpenNURBS/OpenNURBS.git"
+
+    maintainers = ['jrood-nrel']
+
+    version('develop',
+            git='https://github.com/OpenNURBS/OpenNURBS.git',
+            branch='develop')
+
+    version('percept', '59163fd085a24c7a4c2170c70bb60fea',
+            url='https://github.com/PerceptTools/percept/raw/master/build-cmake/opennurbs-percept.tar.gz')
+
+    variant('shared', default=True,
+            description="Build shared libraries")
+
+    # CMake installation method
+    def install(self, spec, prefix):
+        cmake_args = [
+            '-DBUILD_SHARED_LIBS:BOOL=%s' % (
+                'ON' if '+shared' in spec else 'OFF')
+        ]
+
+        cmake_args.extend(std_cmake_args)
+
+        with working_dir('spack-build', create=True):
+            cmake('..', *cmake_args)
+            make()
+            make('install')
+
+    # Pre-cmake installation method
+    @when('@percept')
+    def install(self, spec, prefix):
+        make(parallel=False)
+
+        # Install manually
+        mkdir(prefix.lib)
+        mkdir(prefix.include)
+        install('libopenNURBS.a', prefix.lib)
+        install_tree('zlib', join_path(prefix.include, 'zlib'))
+        headers = glob.glob(join_path('.', '*.h'))
+        for h in headers:
+            install(h, prefix.include)