Detected by 32-bit Windows compiler:

[2024-05-13T03:57:12,215Z] c:\sb\prod\1715572015\workspace\open\src\hotspot\share\utilities\istream.cpp(250): error C2220: the following warning is treated as an error
[2024-05-13T03:57:12,215Z] c:\sb\prod\1715572015\workspace\open\src\hotspot\share\utilities\istream.cpp(250): warning C4267: '=': conversion from 'size_t' to 'char', possible loss of data

The code line is:

    _line_ending = (int)(_next - end);

where _next and end are size_t, and:

  char _line_ending; // one of {0,1,2} for "", "\n", "\r\n"

There is clearly a loss of precision here: size_t -> int -> char, but the cast to int makes the error message unexpected.

Simplest fix is to just make _line_ending an int.