Fix signature for mpfr's set_emin/_emax calls (#32743)

These functions can error and thus return a Cint error code.
Most architectures aren't particularly picky about a mismatched
signature for the return value (particularly something like Cint
that is often ignored), but it is both wrong and can cause problems
on architectures that have strict checking (e.g. wasm).

Author: Keno

base/mpfr.jl

@@ -1031,8 +1031,9 @@ get_emin() = ccall((:mpfr_get_emin, :libmpfr), Clong, ())
 get_emin_min() = ccall((:mpfr_get_emin_min, :libmpfr), Clong, ())
 get_emin_max() = ccall((:mpfr_get_emin_max, :libmpfr), Clong, ())
 
-set_emax!(x) = ccall((:mpfr_set_emax, :libmpfr), Cvoid, (Clong,), x)
-set_emin!(x) = ccall((:mpfr_set_emin, :libmpfr), Cvoid, (Clong,), x)
+check_exponent_err(ret) = ret == 0 || throw(ArgumentError("Invalid MPFR exponent range"))
+set_emax!(x) = check_exponent_err(ccall((:mpfr_set_emax, :libmpfr), Cint, (Clong,), x))
+set_emin!(x) = check_exponent_err(ccall((:mpfr_set_emin, :libmpfr), Cint, (Clong,), x))
 
 function Base.deepcopy_internal(x::BigFloat, stackdict::IdDict)
     haskey(stackdict, x) && return stackdict[x]