This way autom4te uses m4 as it finds it in the PATH, rather than
hardcoding any particular path.
(From OE-Core rev: fd6c84249b7bbb5f51d829cf96cae52fe88f456c)
Signed-off-by: Christopher Larson <kergoth@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>