libpam: be more strict about user's sanity

* replace do_pam_sanity function with distro_features_check inherit
* fixes:
  WARNING: libpam-1.3.0-r5 do_pam_sanity: Building libpam but 'pam' isn't in DISTRO_FEATURES, PAM won't work correctly
  in world builds and prevents user to build libpam at all without pam
  in DISTRO_FEATURES, I don't see any users of this which wouldn't respect
  pam in DISTRO_FEATURES
* only libuser is depending on libpam without respecting DISTRO_FEATURES
* there are few recipes in meta-oe layers depending on libpam without
  respecting DISTRO_FEATURES, I've sent patch for them:
  samba, openwsman, pam-ssh-agent-auth, sblim-sfcb, passwdqc, python-pam, smbnetfs
  and omxplayer in meta-raspberrypi, I've sent PR for that one:
  agherzan/meta-raspberrypi#192
* poky-lsb will need to add pam to DISTRO_FEATURES in order to build
  packagegroup-core-lsb

(From OE-Core rev: 7d05eb3b6dac2ec7711abb6ce6f3e772636aa8dc)

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/libuser/libuser_0.62.bb

@@ -22,6 +22,9 @@ SRC_URI[sha256sum] = "a58ff4fabb01a25043b142185a33eeea961109dd60d4b40b6a9df4fa3c
 
 DEPENDS = "popt libpam glib-2.0 python3"
 
+inherit distro_features_check
+REQUIRED_DISTRO_FEATURES = "pam"
+
 inherit autotools gettext python3native python3-dir pkgconfig gtk-doc
 
 EXTRA_OEMAKE = "PYTHON_CPPFLAGS=-I${STAGING_INCDIR}/${PYTHON_DIR}${PYTHON_ABI}"

meta/recipes-extended/packagegroups/packagegroup-core-lsb.bb

@@ -14,6 +14,9 @@ REQUIRED_DISTRO_FEATURES = "x11"
 # libglu needs virtual/libgl, which requires opengl in DISTRO_FEATURES
 REQUIRED_DISTRO_FEATURES += "opengl"
 
+# libpam, pam-plugin-wheel requires pam in DISTRO_FEATURES
+REQUIRED_DISTRO_FEATURES += "pam"
+
 #
 # We will skip parsing this packagegeoup for non-glibc systems
 #

meta/recipes-extended/pam/libpam_1.3.0.bb

@@ -151,11 +151,8 @@ do_install() {
 	fi
 }
 
-python do_pam_sanity () {
-    if not bb.utils.contains('DISTRO_FEATURES', 'pam', True, False, d):
-        bb.warn("Building libpam but 'pam' isn't in DISTRO_FEATURES, PAM won't work correctly")
-}
-addtask pam_sanity before do_configure
+inherit distro_features_check
+REQUIRED_DISTRO_FEATURES = "pam"
 
 BBCLASSEXTEND = "nativesdk native"