Fix build with GCC 11.2

--- libenctain/botan-1.6/include/base.h

+++ libenctain/botan-1.6/include/base.h

@@ -27,8 +27,8 @@ class SymmetricAlgorithm

       virtual std::string name() const = 0;

-      void set_key(const SymmetricKey&) throw(Invalid_Key_Length);

-      void set_key(const byte[], u32bit) throw(Invalid_Key_Length);

+      void set_key(const SymmetricKey&);

+      void set_key(const byte[], u32bit);

       bool valid_keylength(u32bit) const;

       SymmetricAlgorithm(u32bit, u32bit, u32bit);

       virtual ~SymmetricAlgorithm() {}

@@ -156,7 +156,7 @@ class EntropySource

 class RandomNumberGenerator

    {

    public:

-      virtual void randomize(byte[], u32bit) throw(PRNG_Unseeded) = 0;

+      virtual void randomize(byte[], u32bit) = 0;

       virtual bool is_seeded() const { return true; }

       virtual void clear() throw() {};

--- libenctain/botan-1.6/include/randpool.h

+++ libenctain/botan-1.6/include/randpool.h

@@ -17,7 +17,7 @@ namespace Botan {

 class Randpool : public RandomNumberGenerator

    {

    public:

-      void randomize(byte[], u32bit) throw(PRNG_Unseeded);

+      void randomize(byte[], u32bit);

       bool is_seeded() const;

       void clear() throw();

       std::string name() const;

--- libenctain/botan-1.6/include/x931_rng.h

+++ libenctain/botan-1.6/include/x931_rng.h

@@ -17,7 +17,7 @@ namespace Botan {

 class ANSI_X931_RNG : public RandomNumberGenerator

    {

    public:

-      void randomize(byte[], u32bit) throw(PRNG_Unseeded);

+      void randomize(byte[], u32bit);

       bool is_seeded() const;

       void clear() throw();

       std::string name() const;

--- libenctain/botan-1.6/src/base.cpp

+++ libenctain/botan-1.6/src/base.cpp

@@ -37,7 +37,6 @@ bool SymmetricAlgorithm::valid_keylength(u32bit length) const

 * Set the key                                    *

 *************************************************/

 void SymmetricAlgorithm::set_key(const SymmetricKey& algo_key)

-   throw(Invalid_Key_Length)

    {

    set_key(algo_key.begin(), algo_key.length());

    }

@@ -46,7 +45,6 @@ void SymmetricAlgorithm::set_key(const SymmetricKey& algo_key)

 * Set the key                                    *

 *************************************************/

 void SymmetricAlgorithm::set_key(const byte algo_key[], u32bit length)

-   throw(Invalid_Key_Length)

    {

    if(!valid_keylength(length))

       throw Invalid_Key_Length(name(), length);

--- libenctain/botan-1.6/src/randpool.cpp

+++ libenctain/botan-1.6/src/randpool.cpp

@@ -38,7 +38,7 @@ SecureVector<byte> randpool_prf(MessageAuthenticationCode* mac,

 /*************************************************

 * Generate a buffer of random bytes              *

 *************************************************/

-void Randpool::randomize(byte out[], u32bit length) throw(PRNG_Unseeded)

+void Randpool::randomize(byte out[], u32bit length)

    {

    if(!is_seeded())

       throw PRNG_Unseeded(name());

--- libenctain/botan-1.6/src/x931_rng.cpp

+++ libenctain/botan-1.6/src/x931_rng.cpp

@@ -15,7 +15,7 @@ namespace Botan {

 /*************************************************

 * Generate a buffer of random bytes              *

 *************************************************/

-void ANSI_X931_RNG::randomize(byte out[], u32bit length) throw(PRNG_Unseeded)

+void ANSI_X931_RNG::randomize(byte out[], u32bit length)

    {

    if(!is_seeded())

       throw PRNG_Unseeded(name());