Hide symbols from transient dependencies

[hvge]

Task specification

Hide all symbols from transient dependencies currently provided by PowerAuthCore framework (or .so on Android). Symbols from the following libraries should not be exported in the final module:

• libcrypto (OpenSSL)
• libcc7
• libPowerAuthCoreLib

The reason for this change is that this typically trigger a false positive alerts in some automatic vulnerability scans. For example, OpenSSL currently doesn't support option to turn off MD-5 in the build, so it typically trigger a "broken cryprography" warning, even if we don't use MD-5 at all.

Use -fvisibility=hidden in C compiler flags to do this for each library.

[hvge]

Note that this ticket should be back ported to 1.9.x.