csa-c: added new package at master (#17676)

Co-authored-by: Massimiliano Culpo <massimiliano.culpo@gmail.com>

var/spack/repos/builtin/packages/csa-c/package.py

@@ -0,0 +1,19 @@
+# Copyright 2013-2020 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 CsaC(AutotoolsPackage):
+    """csa: Cubic Spline Approximation. csa is a C code for
+    cubic spline approximation of 2D scattered data. It provides
+    a C library and a command line utility csabathy."""
+
+    homepage = "https://github.com/sakov/csa-c"
+    git      = "https://github.com/sakov/csa-c.git"
+
+    version('master', branch='master')
+
+    configure_directory = 'csa'