Making-tarballs.md

+Command:
+```bash
+cmake -DLCG_INSTALL_PREFIX='/afs/cern.ch/sw/lcg/external/' -DLCG_VERSION=67c -DCMAKE_INSTALL_PREFIX=/afs/cern.ch/sw/lcg/external/ -DLCG_TARBALL_INSTALL=ON  ../lcgcmake/
+```
+
+May need `-DLCG_IGNORE=<package>`.
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