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/tests/test_rng.h b/src/tests/test_rng.h
index 7d30fd6cc..3016707dd 100644
--- a/src/tests/test_rng.h
+++ b/src/tests/test_rng.h
@@ -23,7 +23,7 @@ class Fixed_Output_RNG : public Botan::RandomNumberGenerator
       byte random()
          {
          if(!is_seeded())
-            throw std::runtime_error("Out of bytes");
+            throw Test_Error("Out of bytes");
 
          byte out = buf.front();
          buf.pop_front();