AutotoolsPackage: minor improvements (#2859)

* AutotoolsPackage: added configure_directory to permit build out of source. The configure script executable is now invoked with an absolute path. Modified a few packages accordingly.

* build_systems: functions returning directories are now properties

* build_systems: fixed issues with tcl and tk

* AutotoolsPackage: reworked recipe for autoreconf

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

@@ -38,8 +38,9 @@ class Libgd(AutotoolsPackage):
     """
 
     homepage = "https://github.com/libgd/libgd"
-    url      = "https://github.com/libgd/libgd/archive/gd-2.1.1.tar.gz"
+    url      = 'https://github.com/libgd/libgd/releases/download/gd-2.2.4/libgd-2.2.4.tar.gz'
 
+    version('2.2.4', '0a3c307b5075edbe1883543dd1153c02')
     version('2.2.3', 'a67bd15fa33d4aac0a1c7904aed19f49')
     version('2.1.1', 'e91a1a99903e460e7ba00a794e72cc1e')
 
@@ -54,16 +55,3 @@ class Libgd(AutotoolsPackage):
     depends_on('libpng')
     depends_on('libtiff')
     depends_on('fontconfig')
-
-    def autoreconf(self, spec, prefix):
-        autoreconf("--install", "--force",
-                   "-I", "m4",
-                   "-I", join_path(spec['gettext'].prefix,
-                                   "share", "aclocal"),
-                   "-I", join_path(spec['pkg-config'].prefix,
-                                   "share", "aclocal"),
-                   "-I", join_path(spec['automake'].prefix,
-                                   "share", "aclocal"),
-                   "-I", join_path(spec['libtool'].prefix,
-                                   "share", "aclocal")
-                   )