support/libtool: add patch for newer versions

Add patch to support newer (>2.4.2) versions.
Adjust patch logic to check for patchlevel greater than 2 (apply new patch) or
not (apply current patch).
Some people/distributions used unreleased versions, with the string being
2.4.2.x, this packages are AUTORECONFed and have to be kept like this since
the up-to-2.4.2 patch doesn't work, neither does the from-2.4.3 version patch.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>