Just a heads up that https/ssl support on Linux has now been added to JUCE. Currently, by default, HTTPS/SSL support will be disabled by the introjucer so that no additional dependencies are introduced to already existing JUCE projects. To enable it you will need to rebuild the newest Introjucer (from latest tip on github!) and click on the "juce_core" module in the "Config" tab and select "ENABLED" under "JUCE_USE_CURL" on the right hand side. If you use an old version of Introjucer then you will get linker errors!
Additionally, you will need to install the libcurl development files to use this feature. For example, on Ubuntu/Debian the following should work:
sudo apt-get install libcurl4-gnutls-dev
Note, that the users of your app do not need to install libcurl-dev development files (headers etc). All they need is libcurl which is installed by default on nearly all linux distributions.