autogen: Make sure MAKEFLAGS is not set before running autoreconf

Without this the "w" flag may be set which causes the version
to be incorrectly to be obtains in configure.ac causing configure
to fail miserably

autogen.sh

@@ -11,6 +11,8 @@ if test "x$SRCDIR" != "x$ORIGDIR"; then
 	exit 1
 fi
 
+MAKEFLAGS=""
+
 autoreconf -v --install || exit 1
 
 "$srcdir"/configure "$@"