Added framework to sshbn.c to make it possible to vary the

underlying integer type forming the Bignum. Using this, arranged
that gcc/x86 uses 32-bit chunks rather than the guaranteed ANSI-
portable 16-bit chunks. This has gained another 30% on key exchanges
by my measurements, but I'm not yet convinced that it's all
perfectly robust - it seems to work fine for SSH1 and SSH2/RSA but
I haven't ensured that every bignum routine is actually being
tested, so it may yet show up problems in DSA or key generation.

[originally from svn r3135]

ssh.h

@@ -315,6 +315,10 @@ Bignum bignum_rshift(Bignum number, int shift);
 int bignum_cmp(Bignum a, Bignum b);
 char *bignum_decimal(Bignum x);
 
+#ifdef DEBUG
+void diagbn(char *prefix, Bignum md);
+#endif
+
 void *dh_setup_group1(void);
 void *dh_setup_group(Bignum pval, Bignum gval);
 void dh_cleanup(void *);