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, 11 deletions

diff --git a/libio/stdio.c b/libio/stdio.c
index 1294d28..522de44 100644
--- a/libio/stdio.c
+++ b/libio/stdio.c
@@ -33,14 +33,3 @@
 FILE *stdin = (FILE *) &_IO_2_1_stdin_;
 FILE *stdout = (FILE *) &_IO_2_1_stdout_;
 FILE *stderr = (FILE *) &_IO_2_1_stderr_;
-
-#undef _IO_stdin
-#undef _IO_stdout
-#undef _IO_stderr
-#define AL(name) AL2 (name, _IO_##name)
-#define AL2(name, al) \
-  extern __typeof (name) al __attribute__ ((alias (#name),                    \
-                                            visibility ("hidden")))
-AL(stdin);
-AL(stdout);
-AL(stderr);