fix FP_ILOGB0 and FP_ILOGBNAN definitions to be valid for use in #if

commit 98c9af500125df41fdb46d7e384b00982d72493a wrongly claimed they
do not need to be valid for such usage, but the last sentence of C11
7.1.4 ΒΆ1 imposes a broad requirement that all macros specified as
integer constant expressions also need to be valid for #if.

simply write the value out explicitly. there is no value here in
pretending that the width of int will vary.
1 file changed