libc: newlib: Avoid all files to be opened in line buffer mode

Default buffer mode is setup by fopen depending on isatty value.
Expect only 0, 1 & 2 to be tty for CONFIG_POSIX_API cases.

This way regular files are opened in block buffering mode (instead
of line buffering mode) which really speed up fread/fwrite
operations on FS.

Signed-off-by: Arnaud Mouiche <arnaud.mouiche@invoxia.com>
1 file changed