new package: qwtpolar (#12382)

* create qwtpolar package

* patch config files so that qwtpolar successfully builds

* make flake8 happy

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

@@ -0,0 +1,27 @@
+# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class Qwtpolar(QMakePackage):
+    """The QwtPolar library contains classes for displaying values on a polar
+    coordinate system.
+    """
+
+    homepage = "https://qwtpolar.sourceforge.io"
+    url      = "https://sourceforge.net/projects/qwtpolar/files/qwtpolar/1.1.1/qwtpolar-1.1.1.tar.bz2"
+
+    version('1.1.1', sha256='6168baa9dbc8d527ae1ebf2631313291a1d545da268a05f4caa52ceadbe8b295')
+
+    depends_on('qt@4.4:')
+    depends_on('qwt@6.1:')
+
+    def patch(self):
+        # Modify hardcoded prefix
+        filter_file(r'/usr/local/qwtpolar-\$\$QWT_POLAR_VERSION.*',
+                    self.prefix, 'qwtpolarconfig.pri')
+        # Don't build examples as they're causing qmake to throw errors
+        filter_file(r'QwtPolarExamples', '', 'qwtpolarconfig.pri')