Reroot the exception hierarchy into a toplevel Exception class

As the alternatives are unfortunate for applications trying to catch
all library errors, and it seems deriving from std::runtime_error
causes problems with MSVC DLLs (GH #340)

Effectively reverts 2837e915d82e43

1 files changed, 1 insertions, 1 deletions

diff --git a/src/lib/compression/compression.h b/src/lib/compression/compression.h
index 2c74550d6..0a8079de8 100644
--- a/src/lib/compression/compression.h
+++ b/src/lib/compression/compression.h
@@ -28,7 +28,7 @@ class BOTAN_DLL Compressor_Transform : public Transform
 
       size_t output_length(size_t) const override final
          {
-         throw std::runtime_error(name() + " output length indeterminate");
+         throw Exception(name() + " output length indeterminate");
          }
    };