Thanks for that suggestion and the work in generating that nice patch. One general comment is that there is a lot of duplicate text that perhaps could simply be replaced by an index. E.g., instead of this:
@item btowc On Windows systems, @code{wchar_t} is a 16-bit type and therefore cannot accomodate all Unicode characters. ... @item fgetwc @itemx fgetws On Windows systems, @code{wchar_t} is a 16-bit type and therefore cannot accomodate all Unicode characters. ... @item fputwc @itemx fputws On Windows systems, @code{wchar_t} is a 16-bit type and therefore cannot accomodate all Unicode characters. ... @item fwide On Windows systems, @code{wchar_t} is a 16-bit type and therefore cannot accomodate all Unicode characters. ... (and on and on -- there are lots of these), it would be better to simply have a paragraph like this: On Windows systems, @code{wchar_t} is a 16-bit type and therefore cannot accomodate all Unicode characters. This affects the following functions: btowc fgetwc fputwc fputws fwide ... and then create an index of all the functions that have portability implications, and plant entries for btowc etc. in this index. Or perhaps we could reuse one of the existing Autoconf indices for this purpose. Using an index would make the main text shorter and much easier to read, and the index would let people look up info about each function as needed.