Gmp.mpq: Fixed linking error with old libgmp.
Compiler: Improved robustness in low_describe_type().

It didn't like markers in the string range (which are
now generated for the sprintf type).
Compiler: Some more of the same.
Compiler: Fixed some typos.
7.4::Crypto: Fix hmac
BSON: Remove unaligned memory accesses
[sparc] Fixed bug introduced by the svalue renumbering.

The svalue type fields were set from a dirty register when pushing
the zero integer.

Fixes the fatal "Invalid type 120 in svalue at xxxxxxxx.", and similar.
Nettle: Arctwo isn't available in old versions of Nettle.

Fixes compatibility with Nettle 1.15.
Testsuite: Fixed a few sprintf() return type tests.

Updated to know about the string(8bit) short hand.