Massive conversion from Package to AutotoolsPackage (#2845)

* Massive conversion from Package to AutotoolsPackage

* Forgot to convert p4est to AutotoolsPackage

* Fix typo

* Fix broken link in docs

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

@@ -25,7 +25,7 @@
 from spack import *
 
 
-class Sessreg(Package):
+class Sessreg(AutotoolsPackage):
     """Sessreg is a simple program for managing utmp/wtmp entries for X
     sessions. It was originally written for use with xdm, but may also be
     used with other display managers such as gdm or kdm."""
@@ -43,9 +43,3 @@ def patch(self):
         kwargs = {'string': True}
         filter_file('$(CPP) $(DEFS)', '$(CPP) -P $(DEFS)',
                     'man/Makefile.in', **kwargs)
-
-    def install(self, spec, prefix):
-        configure('--prefix={0}'.format(prefix))
-
-        make()
-        make('install')