* lang/cpp/src/context.h (enum EncryptionFlags): Add constant
EncryptFile.
* lang/cpp/src/global.h (enum SignatureMode): Add constant SignFile.
* lang/cpp/src/context.cpp (sigflags2sigflags): Handle new flag
SignFile.
(encryptflags2encryptflags): Handle new flag EncryptFile.
(operator<<): Add new flags to the corresponding debug streams.
* lang/cpp/src/signingresult.cpp (CreatedSignature::mode): Handle
new flag SignFile (even if it cannot occur).