BuildSystem: Automatically delete libtool files

Half of the ports had a manual post_install step to delete libtool files
this is now done automatically and there is no need for it!

Libtool files have to be deleted as libtool doesn't work while
cross-compiling (at least out of the box)

ports/libogg/build.sh

@@ -4,8 +4,3 @@ NAME='libogg'
 VERSION='1.3.6'
 DOWNLOAD_URL="https://github.com/xiph/ogg/releases/download/v$VERSION/libogg-$VERSION.tar.gz#83e6704730683d004d20e21b8f7f55dcb3383cdf84c0daedf30bde175f774638"
 CONFIG_SUB=('config.sub')
-
-post_install() {
-	# remove libtool file
-	rm -f $BANAN_SYSROOT/usr/lib/libogg.la
-}