autotools.bbclass: Make builds deterministic

We need to ensure any aclocal-copy directory is removed before we s
earch for .m4 files, else the locations .m4 files are found from can
vary depending on whether its the first or second time we run configure.

Clearing any existing aclocal-copy directory before we start resolves
this issue and makes builds deterministic again.

(From OE-Core rev: 673e2a05013cbe08efde936f663845031025689d)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/autotools.bbclass

@@ -102,6 +102,8 @@ autotools_do_configure() {
 		if [ -e ${S}/configure.in -o -e ${S}/configure.ac ]; then
 			olddir=`pwd`
 			cd ${S}
+			# Remove any previous copy of the m4 macros
+			rm -rf ${B}/aclocal-copy/
 			if [ x"${acpaths}" = xdefault ]; then
 				acpaths=
 				for i in `find ${S} -maxdepth 2 -name \*.m4|grep -v 'aclocal.m4'| \