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/libjpeg/build.sh

@@ -5,8 +5,3 @@ VERSION='9f'
 DOWNLOAD_URL="https://www.ijg.org/files/jpegsrc.v9f.tar.gz#04705c110cb2469caa79fb71fba3d7bf834914706e9641a4589485c1f832565b"
 TAR_CONTENT="jpeg-$VERSION"
 CONFIG_SUB=('config.sub')
-
-post_install() {
-	# remove libtool files
-	rm -f $BANAN_SYSROOT/usr/lib/libjpeg.la
-}