libio: Eliminate _IO_stdin, _IO_stdout, _IO_stderr

These variables are only used to determine if a stdio stream is
a pre-allocated stream, but it is possible to do so by comparing
a FILE * to all pre-allocated stream objects.  As a result, it is
not necessary to keep those pointers in separate variables.

Behavior with symbol interposition is unchanged because _IO_stdin_,
_IO_stdout_, _IO_stderr_ are exported, and refer to objects outside of
libc if symbol interposition or copy relocations are involved.  (The
removed variables _IO_stdin, _IO_stdout, _IO_stderr were not exported,
of course.)

1 files changed, 0 insertions, 3 deletions

diff --git a/libio/libio.h b/libio/libio.h
index 9c08c7eba1..c38095ff77 100644
--- a/libio/libio.h
+++ b/libio/libio.h
@@ -185,9 +185,6 @@ struct _IO_FILE_plus;
 extern struct _IO_FILE_plus _IO_2_1_stdin_;
 extern struct _IO_FILE_plus _IO_2_1_stdout_;
 extern struct _IO_FILE_plus _IO_2_1_stderr_;
-extern FILE *_IO_stdin attribute_hidden;
-extern FILE *_IO_stdout attribute_hidden;
-extern FILE *_IO_stderr attribute_hidden;
 
 struct _IO_cookie_file;