I guess you should be able to compile ROOT 5.34/38 thought I would say that you should better take the head of the v5-34-00-patches branch (you may need to add “--enable-gsl-shared --disable-fitsio” when configuring it) for ROOT 5 or the newest ROOT 6 release.
Maybe the problem is that “curl” actually tries to download files using “https”, not “http” (and maybe it is missing an appropriate “proxy”). You need to make sure that the following command works:
curl -L https://github.com/lz4/lz4/archive/v1.7.5.tar.gz > 1.7.5.tar.gz