utils.bbclass: add helper function to add all multilib variants of a specific package

This is useful for the scenario where we want to add 'gcc' to
the root file system for all multilib variants

(From OE-Core rev: 7cd54693363882854cd026ebe071e9f2e03d364e)

Signed-off-by: Matthew McClintock <msm@freescale.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/utils.bbclass

@@ -325,6 +325,15 @@ def extend_variants(d, var, extend, delim=':'):
 			variants.append(eext[1])
 	return " ".join(variants)
 
+def multilib_pkg_extend(d, pkg):
+	variants = (d.getVar("MULTILIB_VARIANTS", True) or "").split()
+	if not variants:
+	    return pkg
+	pkgs = pkg
+	for v in variants:
+	    pkgs = pkgs + " " + v + "-" + pkg
+	return pkgs
+
 def all_multilib_tune_values(d, var, unique = True, need_split = True, delim = ' '):
 	"""Return a string of all ${var} in all multilib tune configuration"""
 	values = []