added package.py for rgsl (from auto-generated template)

packages/rgsl/package.py

+from spack.package import *
+
+
+class Rgsl(RPackage):
+    """This is an interface package to solve ODE systems using gsl_odeiv2 within R. The system to solave has to be defined using C code: a shared library, dynamically loaded by this package when solving."""
+
+    homepage = "https://github.com/icpm-kth/rgsl"
+    url = "https://github.com/icpm-kth/rgsl/archive/refs/tags/v0.1.tar.gz"
+    version("0.1.0", sha256="dd6a14dda8731f4cf32149c8a9842e4e2ba424c8404f4d6839108153b20e4c3e")
+
+    # GNU Scientific Library: https://www.gnu.org/software/gsl
+    # spack: https://spack.readthedocs.io/en/latest/package_list.html#gsl
+    depends_on("gsl")
+
+    def install(self, spec, prefix):
+        make()
+        make("install")