file from a bio or fp. Added some more constification to the BN library.

This also avoids the problems with SC4.2 and unpatched SC5.

Submitted by: Andy Polyakov <appro@fy.chalmers.se>

Submitted by: Richard Levitte <richard@levitte.org>

when they cause the destination to expand.

To see how evil this is try this:

#include <pem.h>
main()
{
	BIGNUM *bn = NULL;
        int i;
	bn = BN_new();
	BN_hex2bn(&bn, "FFFFFFFF");
	BN_add_word(bn, 1);
	printf("Value %s\n", BN_bn2hex(bn));
}

This would typically fail before the patch.

It also screws up if you comment out the BN_hex2bn line above or in any
situation where BN_add_word() causes the number of BN_ULONGs in the result
to change (try doubling the number of FFs).

1. The already released version was 0.9.1c and not 0.9.1b

2. The next release should be 0.9.2 and not 0.9.1d, because
   first the changes are already too large, second we should avoid any more
   0.9.1x confusions and third, the Apache version semantics of
   VERSION.REVISION.PATCHLEVEL for the version string is reasonable (and here
   .2 is already just a patchlevel and not major change).
tVS: ----------------------------------------------------------------------