[Bug libfortran/91030] Poor performance of I/O -fconvert=big-endian

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91030

--- Comment #16 from David Edelsohn <dje at gcc dot gnu.org> ---
libgfortran unix.c:raw_write() will access the WRITE system call with up to 2GB
of data, which the testcase is using for the native format.

Should libgfortran I/O buffer at least use sysconf(_SC_PAGESIZE) instead of
hard coding 8192?