This build adds upstream patches 12 and 13:

• The mpfr_get_str_ndigits function may raise the inexact flag. In a very reduced exponent range (e.g. in which the result would not be representable as a MPFR number), it has undefined behavior: it may return an incorrect value, crash, or loop, taking more and more memory. This is fixed by the get_str_ndigits patch, which also updates the tests to check these issues. Corresponding changeset in the 4.1 branch: 14490.
• The code for the formatted output functions (mpfr_printf, etc.) contains an incorrect assertion, checked only in debug mode, i.e. when MPFR has been configured with --enable-assert; this assertion failure occurs when the integer 0 (of either a native type or mpfr_prec_t with the length specifier P) is output with the precision field equal to 0, i.e. when the corresponding string to output is empty. Otherwise, there should be no side effects since the code is actually valid in this case; but since the code incorrectly instructs the compiler that some variable cannot be 0, there might be an issue with some optimizations (very unlikely, though). This bug is fixed by the vasprintf-prec-zero patch, which also provides testcases. Corresponding changesets in the 4.1 branch: 14524, 14525.