Libconfuse: refine autoreconf and add some dependencies (#21006)

* libconfuse: add some build dependencies

* libconfuse: use autogen.sh to do the autoreconf

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

@@ -19,3 +19,9 @@ class Libconfuse(AutotoolsPackage):
     depends_on('autoconf', type='build')
     depends_on('automake', type='build')
     depends_on('libtool',  type='build')
+    depends_on('gettext',  type='build')
+    depends_on('flex',     type='build')
+
+    def autoreconf(self, spec, prefix):
+        bash = which('bash')
+        bash('./autogen.sh')