Revert "Stop converting relative symlinks to absolute."

This reverts commit 9ae3638429.

This change is ok, but cannot be used right now because all existing
binpkgs were created with an old xbps-create(8).

bin/xbps-pkgdb/check_pkg_symlinks.c

@@ -77,7 +77,7 @@ check_pkg_symlinks(struct xbps_handle *xhp, const char *pkgname, void *arg)
 			continue;
 		}
 		snprintf(path, sizeof(path), "%s/%s", xhp->rootdir, file);
-		if ((lnk = xbps_symlink_target(path)) == NULL) {
+		if ((lnk = xbps_symlink_target(xhp, path, tgt)) == NULL) {
 			xbps_error_printf("%s: broken symlink %s (target: %s)\n", pkgname, file, tgt);
 			broken = true;
 			continue;