Determine GMP version

[Sisyphus]

Hi,

Is there a preprocessor command that will determine the version of the GMP
library ? This could be useful if we want to use mpz_combit and/or
mpz_rootrem (which are new in 4.2):

#ifdef symbolThatSpecifies4.2
// we can code using mpz_combit and mpz_rootrem
#else
// we need to code using a workaround
#endif

Cheers,
Rob